My narcissistic brother.

He's 2 years younger than me and I've always thought that he was retarded. He got ran over when we were kids he was about 5 years old and after that I think that something is wrong with his brain. He's very childish and he has spent most of his life playing video games. He refuses to get a full-time job has been working his crappy little part-time dishwasher job for some years now about 10 maybe. He doesn't drive or have friends or a girlfriend. I've always suspected that he's gay or something due to his sassy feminine attitude. About 2 to 3 years ago he started talking crap about me for some reason randomly with some lady that my mom is friends with. He and another sibling of mine had a fallout between them. He then got me in the middle and for some reason he keeps talking crap about me. He'll talk so much s*** about me but will never say it to my face. He has tried to form a smear campaign against me with miserable middle-aged women that he wants to be friends with but they just think he's a weirdo. He has tried to turn my own child against me before but it backfired. I don't know why a brother would have these hateful behaviors towards their own sister I could see a petty jealous sister doing this to their sister maybe but a brother? A supposed male? I don't know what's wrong with him he's really weird. I always hear that he's been talking crap about me through people or other family members I'm just like what the hell!? is he gay what does he hate me? So how can I deal with this I never react to him and I think it drives him crazy and I just ignore him and don't talk to him.