I see celebrities are calling on Trump to do something.
There is nothing Trump can do, it is up to the family, friends and community of disturbed people to help. This is one of the more extreme cases but the more usual result is someone taking their own life, and after that everyone is saying why did they not ask for help. If they are disturbed they often have paranoia which stops them asking, but people who know them can see something is wrong, if they can't help they need to find someone who can help, usually all it takes is a little time but nowadays nobody has that time to help.
I hope the people that expelled him from school really do some soul searching about whether his anti-social behavior was a cry for help or an excuse for them to exercise their power and control in the matter.