@freddie11 I’m sorry you’re going through this and your son too.
Four ideas I have that might help him:
1.) ask your son if he is willing to take some ongoing and continuous self-defense classes. Do your due diligence to find a place with good teachers that are good PEOPLE. This could help him build a community outside of school and also learn self defense if ever in the unfortunate circumstance someone tries to physically attack him, he can defend himself
2.) spend quality time with him. Make sure he knows you’re paying attention to him throughout the day when you’re with him and checking in with him, and that he knows you’re there for him. Perhaps do some bonding activities together like going on walks or watching a movie or playing a game.
3.) help him find hobbies of his own. Could be a STEM club for young adults, learning an instrument, finding a sport, art, cooking, woodwork, horse riding, writing, etc. do some research on all the different hobbies out there (there’s thousands) and start taking him to places that offer that until he finds something he likes.
4.) get a counselor for him.