adult half brother still lives at home

I am 16 and my half brother is 41 and still lives in the house. He has caused our family unimaginable suffering and he just will not leave no matter what. He claims to be disabled and has many different health problems, but works as a watchman so that doesn't make sense at all.

Plus he is not the only one with health problems in the house and he cries about them like an actual toddler, but we all have health problems and he acts like he's the only one and it ****es me off so much. This is one of the multitude of crappy reasons he will not get out the house.

My mother, my sister and I are far past our wits end but my dad is elderly and an EXTREME pushover and is way too scared of him to do anything. He has also threatened our lives many times, and he bad mouths us to all of his grown friends as well, and somehow they are on his side despite the fact he is a grown ass man living in his father's house despite us barely being related to him. Makes sense.

He taunts me all day and then says he doesn't ever talk to me. He purposely comes into the kitchen whenever I do and intently watches what I'm doing and it makes me so uncomfortable. He will literally just stand there looking at what I'm eating or doing and will comment on it, try to joke with me, insult me, tell me how much he used to do for me when I was a child (he used to give me sweets often and now holds that against me everyday), screams at me, says I am rude and an array of other fruitful things.

My dad has also quite literally given him the money to leave but he has put it into investments or stocks or whatever and claims that it is under my dad's name. He also says he will only leave once our dad dies.

There is so, so much more I could say but this would be about 30 pages long then. My sister has gone to uni and he's still here. My parents want me to stay at home for uni but how can I if everyday I will come home to him. I don't know what to do. He screams like a child claiming this is his childhood home and he will not leave. I cannot even articulate how I feel.