Absolutely horrible 16 year old, need help/advice

I am actually a sibling (19f), not a parent, but our parents have completely swept this under the rug so it's me or nobody. I am at my wits end with my parents ignoring this problem while we all (me and them, and arguably his friends) take the brunt of it. Someone has to sort this out and it's not gonna be them!I'm really not a psychologist so there's no way I could definitely get to the root of this, but one factor is that my parents are so scared of my brother's violent outbursts that they gave up on any real parenting years ago.My 16 y/o brother is a disgusting person.He has been allowed to grow up with little to no regulation (when they do threaten discipline, which is rare, 99% of the time he bullies his way out of it, or into a better deal, which has taught him he can get away with anything).He had a girlfriend last year and I used to overhear phone conversations, and he would treat her like she was some sort of dog or emotional punching bag. The sort of things he was saying to her were unbelievable, and this is coming from someone who had grown up with him treating me like crap every day.To us, he is somewhat violent (he will push people when angry and has hit us on occasion).He is entitled - he acts like he owns the world - nothing is ever enough for him, and he has never lifted a finger to help anyone else or even do his own chores (I mean never - he throws his washing on the floor for mum to pick up, his room stinks, once we left him at home for 24 hours and our pets went without food, he leaves his breakfast mess for us to clean...). It's honestly like he doesn't care what happens to other people, and he thinks we are just there to serve him.And he is so disrespectful. The swearing, the arrogance (much more than the average teenager crap that we all go through). He screams on his computer games til 3am every day and doesn't care whether we can get some sleep or focus on our own stuff over all that noise. I actually recently bought him some headphones because he said it would "be easier to talk quietly with these ones", and he's just as loud now. When I try to take them from him he just physically hurts me. He insults my parents' religion just for kicks, to their faces.P.S. Please don't tell me to move out - I get that it's the obvious response and I have of course considered it, but for unrelated reasons it is impossible at this time. via /r/Parenting http://ift.tt/2pIUMOi