This is what admin is supposed to do. Glad he had your back.

My suggestion would be to talk to your principal about the possibility of having the student moved at will if there is any further serious misbehaviour in the future. If there is that possibility, maybe maybe tell the student that he is on his last legs and you need.tonsee.a serious improvement from him and that any further misbehaviour will result in him being reassigned. Have this written and signed by all parties, including parents.

If they put up one bit of fuss, move him. If he starts seriously misbehaving again (he won't change overnight, but any more threats, any more violence, then get him out of there. No it's ands or buts. Don't even tell him before you tell the principal, don't use it as a threat.

If there isn't the possibility to move.him at a later.date, do it now.