I'd honestly feel bad for the dude if he wasn't threatening his roommates, girlfriend and child.
Schizophrenia or any related mental disorder is life destroying, and incredibly difficult to deal with because the delusions take a while to build up. It starts very minor, not being able to tell if one of your random inner thoughts was someone actually saying something. Gradually it becomes more fear based, and because you can't separate your thoughts from reality all of your imagined fears become real. Stray thought about a roommate doing something suspicious? They must be out to get you, why are they out to get you, are these dirty dishes and the way they looked at you Tuesday clues? Are they planning your demise? Do they hate you? Want you dead?
He's already at the point of no return if he's threatening to kill his roommates and slashing their mattresses. He either gets put away, forced to take his medications with weekly checks, or he is going to hurt someone. No in between.