Obviously have to fire the teacher and he can never work in a classroom again. Gotta have more control than that. I've had kids get crazy antagonistic in the classroom, still had to maintain my cool.
But if the entire confrontation is as they say, I wouldn't charge him if I were the D.A. The kid and the teacher both need to get into some sort of program to control their issues, but that teacher don't deserve a record for another man setting him off like that.
The way the kids were acting, when a classroom is that far out of control, it is the entire school culture that's at fault, not just one teacher. And just stupid that they even have phones available to all be taping, every bit of research out there is showing how that destroys learning.