Just to head this off at the pass, because someone is bound to bring up exposure therapy: hi, hello, I am someone who has been through exposure therapy (technically Exposure/Response Prevention, or ERP). Yes, it is broadly speaking true that avoiding triggers increases anxiety in the long run. However, one thing that was stressed to me over and over in ERP is that exposures have to be VOLUNTARY to be beneficial. Meaning, just hucking a tarantula at someone with arachnophobia is going to do far more harm than good. Likewise showing them a bunch of pictures of spiders with no warning. However, putting a content warning puts the decision to engage back into the hands of the person with the phobia (or trauma, eating disorder, etc), which effectively turns it into a voluntary exposure should they choose to engage.
Content/trigger warnings are not about "being shielded from hardship;" they're about not springing trauma triggers or upsetting shit on unsuspecting people (or not causing actual physical harm to people, in the case of epilepsy warnings).
Like, OK, cool, you read Mein Kampf. I don't think that's a bad thing to do, for the reasons you did it. But you did that freely and knowing what you were getting into ("by Adolf Hitler" serves as an implicit content warning IMO). Suppose you were a Jewish student and your history teacher sprung a reading from Mein Kampf in the middle of a lesson with no warning. Or hell, just imagine having "Old Yeller" sprung on you the day after your dog died. I don't think it's babying anyone to warn them about something that could ruin their day.
The game Look Outside has a bunch of fake video games in it that your character can play to get XP and learn skills, and there's some funny character interactions with them. Likewise the Sims series has games that your sims can play.
There's also SBURB from Homestuck (which starts as a video game at least) and the various games from Kidd Radd, which I don't know if that's archived anywhere but I hope it is [EDIT: It is indeed!]
These are just a handful of these types of stories, there's loads more if you want to search for them. But the upshot is: your family or tribe would have taken care of you to the best of their ability, for as long as they could, and you would have been given a decent burial when you died.
Your best bet might be to try and pivot to in-person college/university if possible. You didn't say where you are in the world, but in the US, most schools will have on-campus housing you'd be able to stay in for most of the year. The financial part is always the limiting factor of course, but considering how violent your brother can get, it may be worth it. It's a lot easier to recover from student loan debt than being dead.
It's specifically the fact that it's family that makes it hard for me to buy that it's isolated (hence "in this case"). It's possible for sure, but you don't usually get "my dad picklocked my bedroom door to try and catch me jerking off" without a shitload of other family weirdness.
Just to head this off at the pass, because someone is bound to bring up exposure therapy: hi, hello, I am someone who has been through exposure therapy (technically Exposure/Response Prevention, or ERP). Yes, it is broadly speaking true that avoiding triggers increases anxiety in the long run. However, one thing that was stressed to me over and over in ERP is that exposures have to be VOLUNTARY to be beneficial. Meaning, just hucking a tarantula at someone with arachnophobia is going to do far more harm than good. Likewise showing them a bunch of pictures of spiders with no warning. However, putting a content warning puts the decision to engage back into the hands of the person with the phobia (or trauma, eating disorder, etc), which effectively turns it into a voluntary exposure should they choose to engage.