[Secure Journaling App] Implement strong legal and technical privacy guarantees for entries

Alright y'all, I've been a lurker for a long time but it's finally time I get some clarity from strangers. I've never done more than comment on Reddit, so sorry if my formatting is bad. Sorry for the long post! So, when I was 5, my older sister passed away. Very sad. My brother (which I will call W) was either just becoming an adult or was already one. (We were a big blended family, so I don't actually remember how old he was/is, but he's 12+ years older than me.) My sister's funeral was the last time I had seen or really heard from my brother. He moved to Northern California from Southern California the first opportunity he got with his new wife, he took on a step-son, trying to hold down a job, etc. I never really held the lack of contact against him because my sisters would live with their moms in Tennessee, and W would live with his mom some parts of the year, so distance and being busy was familiar. Frankly, he's always just been more of a name in the list of siblings than actually close. I have some very vague positive memories of playing video games with him, but I was 5 and under at the time, I'm now 27. Anyway, flash forward 10 years after my sister's funeral. One of my other older brothers (who we'll call P) moved up north in that time as well, and he and his wife had a kid. P would fund the gas and food and lodging for my parents and myself to come visit them and the baby so we were up north about once a month. My parents were horribly in debt otherwise and couldn't afford to travel much. Eventually, W asked if they could make a detour to come say Hi on one of the trips and they agreed. This was the first time I'd seen W in 10 years. He looked the same but older, was still warm toward me, kind. It was really nice! While at this short visit, it was decided that I would spend a month at W's home. I don't remember my input being asked and it fits my parents to have someone take us for a while when they needed a break, so this also wasn't new. Despite that, I was really excited to reconnect with my brother as a teenager. I was, however, also aware that W threw out another of our brothers that was living with him when he turned 18, on his birthday, for having a girlfriend that already had a kid (so ironic, from a step father, right?) I thought nothing could happen to me and my other brother just caused the kick out somehow. I was around 15 or so, loved video games, anime, talking with my online friends, technology, and learning crafts. He loved video games, drawing, anime, and technology and nerd shit too, so I was so certain this would be the best trip of my life! I had pictured us playing video games, watching anime, me learning to draw from him (he's truly an excellent artist), us interacting, etc. what I got instead was honestly one of the worst months of my life, and that's saying a lot. The first rule was that I couldn't use technology for more than an hour a day. That meant TV, laptop, video games, phones, _anything_ that used power and wasn't a household appliance. This rule only applied to me, not his step son/my step nephew who was either 1 or 2 years older than me, not anyone else in the house, not any of my nephew's friends, just me. If I talked to my mom on the house phone for an hour, I couldn't play video games, touch my laptop, cell phone, or watch tv in the family room. The family room was where I was told to stay in and sleep as my room for the month. The second rule was that I wasn't allowed to talk to my nephew's friend because he was known for trying to get into the pants of younger girls. He was either 16 or 17 and would target 12-15 year olds. I was expressly warned of this by W. This friend was over almost every single day, and when he would spend the night, they would have him sleep on the floor next to the couch I was on. I felt terribly unsafe. Otherwise, it was expected to be business as usual for me, except I was a techno-holic at that point like every teenager was/is, and I only had online friends due to being a bit of a weirdo. I also had a girlfriend at the time and could only steal my phone and send her good morning texts so I could use my tech time to keep me sane. The only person who gave me something to actually do was my W's wife's mother. She was an elderly woman living with them and she taught me how to embroider. She was a star, a delight, and she was who got me through that whole mess. She also gave me a notebook, which I started to draw in and keep as a diary. After about a week, I started having really negative thoughts about my family and my self. I felt isolated, alone, bored (I have ADHD), and utterly unseen. I embroidered or drew or wrote for the next week, and things bubbled up worse. As they did, my diary entries got darker and more angry and upset. What did I do wrong to be singled out and isolated? The technology rule tightened down so much that I wasn't even allowed to watch my nephew and his perv friend play God of War if I had spent my tech time. I had to turn away from the screen and work on whatever I had in my hands. They also started forcing me to eat foods that made me want to vomit. I was a picky child and still am fairly picky, and they would sit there and scream at me well past dinner time until I ate the food and went and threw it up. They listened in on my calls to my mom too in order to see what I was saying to her. They would sit in the kitchen while I used the house phone while I tried to signal to my mom I needed to be saved. I know this all seems a little much but from my teenage perspective, this was the most isolated I had ever been. W's wife turned out to be the one behind all this. I found out shortly after a sobbing break down begging to know why this was happening that my father had expressed concern that I was on my tech too much, and she ran wild with it. She also let my nephew's pervy friend chase me with a full metal stock pot of boiling water through the cemetery across from their house, and according to her I was in the wrong at the end for giving him my best nutshot with my pointy boots. I started to write in my diary how much I hated them and hated life, I started drawing emo broken hearts all taped back up, I called his wife a b and c word but please note that I was given actual permission to curse as much as I wanted by them so this was a use of that freedom. My catchphrase in the diary became "Death be thy savior." I let all my anger out in the diary so I could be respectful and controlled when I was around them. With all that set up, I can finally get to the ultimate betrayal for me. A week before my mom was supposed to pick me up, W's wife's mother ate an entire container of grape tomatoes and my brother and his wife had an absolute meltdown screaming match about how she ate too much, she was inconsiderate, and much more that I can't remember now but was disgusted by then. They put up one of those baby gates and trapped her in her room since she was too frail and old to take it down. I cried to myself and wrote in my diary. By this time (week 3), I was sleeping with the diary clutched to my chest and never was without it because I knew what I had wrote and had trust issues to start with. I will admit that I did go against the rules and stowed my cell phone in the shower a few times to call my girlfriend and tell her I loved her and to pass some messages to my friends, but otherwise I was an excellently behaved child, at least outwardly. The day after everything with the tomatoes, my brother and his family actually made an effort to spend time with me by proposing going for a walk. I was ecstatic! I was actually going to get to DO something! I left the diary under the couch cushion and went with them. We're all overweight, I was the smallest of us in both age and stature, with his wife and step son being the biggest. We went for about a quarter mile lap around the area when his wife and my nephew said they wanted to go home and were tired. W said "Hey, we're both [Last Name]'s! We don't do things half way, let's go for another lap!" Our family name is something we've always been very proud of. Some of you may see where this is going. Time to put in your guesses on what happened next! If you guessed that my brother used our family name to manipulate me away while his wife found and read every word of my diary, you get a cookie! As we were walking up to the house, his wife sat on the porch, holding the diary up cartoonishly to make sure I saw what she was reading. My brother condescended to me that our dad never kept secrets in the family which was a blatant lie that maybe he was raised with, but I sure wasn't. I thought my world was over at that point. I don't remember much of the confrontation after lunging for the journal. No one physically hurt anyone, but I was punished and berated severely for what I wrote about her specifically. They took away all technology at all and made me sit in the corner and be grateful they didn't break everything I brought with me. So the moment I had my opportunity, I used the house phone, called my mom sobbing, and begged her to come get me. She told me I would have to endure for one more week because we didn't have gas money. I told her that there wouldn't be another week here and I'd find my way home if she couldn't get me. It was 4 hours later that P showed up outside the house, collected me, told W to call the family when "you get your balls off of your wife's shelf", and took me to his home for the remainder of the week. The week with P, his wife, and his baby was the best possible thing for me. I was still sour about my dad giving them ammunition to make those stupid rules, I was hurt that my privacy had been violated, and still had a lot of negative thoughts, but P helped me process a lot of it through talking with my online friends and letting me beat him at video games. Things started to feel right again. By the time mom came to pick me up, I was more myself, and told her everything, including them refusing to return my diary. She tried to get them to send me it because I wanted my drawings out of it, but they claim it got "lost in the mail." P said he wished I'd said they had it when he picked me up because he would have ensured I had it back. That was over 10 years ago. In the time since, I have engaged with W over Facebook messenger twice with crap results, we talked over the phone awkwardly for a few moments where he said he missed hearing from me when my mom died a few years ago, I told him he knows what I expect, and the same year they sent me a Christmas card with both of their cell phone numbers on it. I still don't know who gave them my current address and am furious about it. I assume it was my dad. My whole family knows that I don't talk to him. I still have him added on Facebook, and he knows I'm waiting for a direct and explicit apology for what he did. I genuinely don't want anything to do with him, but I have always kept a path open for an apology. This came up recently and My dad thinks I'm the AH for holding a grudge this long, I think I'm in the right for refusing to tolerate someone who abused me for a month straight, abused a frail old lady who's dead now, and backstabbed me with my own family name. I have a massive fear of my diary being used against me in any way, especially through something like a subpoena where I don't get a choice, so I don't keep one. I want to desperately, but I can't get myself to keep records of my thoughts just in case someone might get a hair up their ass. If I do ever write, I don't write my real feeling. The only time I write down my actual feelings, I burn the paper after. Tl;dr: My older brother emotionally abused me as a teenager for a month and used my angsty teenage diary against me to punish me for what I wrote. I haven't forgiven him 10+ years later and every few years he tries to poke into my life without an apology. Dad thinks I'm an ass for not forgiving him. So, Reddit, hit me with what you think, AITAH?