Okay, let's start this off nice and simple. This kid is harmless… physically. 

Whenever this kid has mental breakdowns, apparently he needs to talk about how he wants to kill everyone and then himself, or display extremely homophobic and Nazi-like behavior.

No one does anything about this. The teachers don't care about it and they have said to my boyfriend that he just has to live with it.

He has told my boyfriend that he wants him to suffer, that he's going to stab him, and that he should kill himself. I broke down in tears.

I don't think he should have to put up with this, and neither does he. He's gone to the principal, but all they've done is they've hired a social worker to counsel him. I don't think this is enough, and think that he should either be expelled, or locked up.

AITA?