Advice desperately needed

So when it comes to a relationship with my mom it’s hot and cold. She’s always had favorites, my older sibling and my little brother. And before you say middle child syndrome every Christmas they both get more presents and more expensive things, she gets all of mine from wish and takes anything back that she likes. Ordered me rabbit fur boots after finding out I’m highly against the fur industry. She’s hit me before because she was mad at my brother, left me with a child predator, I got molested and she lied to my dad and said it never happened. I miscarried and she shrugged and said it happens and then proceeded to put a new born in my arms to carry because my aunt needed rest. I’ve attempted suicide multiple times and my moms comment was “well you shouldn’t have made it past 13 but you’re f*cking stubborn@ Anyways. My little brother has grown up with absolutely no discipline, and he’s psychotic. And I mean literally I’m so scared to be around him I bought locks for my doors bought a gun. I have no way to leave the house right now. He’s came in my room when I was sleeping naked to watch me and he’s walked around in the middle of the night with kitchen knives, he has 27 no contact orders with other kids because he threatened to burn their churches down. The school has complained he needs counseling and I’ve mentioned he maybe needs in patient care. Today me and my mom got into a huge fight because he was being so disrespectful and I corrected him. She told me it wasn’t my place and my coworker piped up and said it’s not like my mother does anything to correct the behavior anyways. And now I might not have a place to live, my college could be defunded. I’m scared to go home but idk how to diffuse this situation. I just need help