Opinion needed

Well don't know if I'm putting this in the right place but anyways need opinions. Well my son beat up this girl bad last night and I didn't even know it until today. But he has done this four times to different girls. I don't have a good relationship with my son at all. He trys to manipulate people trying to make u believe that someone else is crazy or is bad but he does that to hide the way he really is. He has mental issues. He's been in hospitals 3 times in his life. He has told me after a major surgery to my chest that he wish I die and recently sad this and called me a b because he couldn't get his way. I am to the point now where I have let him go. I have done everything I could to make sure he did everything in his life right but he did other wise. Now I'm just recently finding out he's on cocaine powder. So the family of the girl is threatening to kill him and bad as I really wanted to say that it's get u first I think of how he did this girl and how she told me that she thought she was going to lose her life because not only did he knock her out he had a knife. I really feel that my work is done. I was in a abusive relationship and told my son and he grew up and beat up the due but he can go and do this to another girl like I was when it happened to me. My sympathy is for that girl that suffered that abuse not my son. And I don't feel sorry for him. I feel he doesn't need to come back her to risk getting killed I feel he needs to go get that mental help that he's been needing. He tried hurting his self I sent him to the hospital and my son told that doctor things to were the doctor went off on me saying that there was nothing wrong with my son and that my son told him that I was trying to get him a check to take it. That was the most weirdest thing I've ever seen or heard happen. But since that doctor didn't help him now his situation has gotten worse and he is seriously hurting girls, and he's talking about killing his self SMH. Give me ur thoughts and opinions even if you feel that I'm right or wrong for now washing my hands him.