Firstly HUGE {{{HUGS}}} its so upsetting isnt it, to watch your child being self destructive and not even realising it?
im sorry i dont have much advice either...
DS1 (adhd) was taken out of school at the end of year 5, because of his behaviour - not violent, but much more unmanageable. He copied everyones bad behaviour and multiplied it!Because of his difficulties with social acceptability he didn't know where the 'line' was, and frequently 'ran right past it'!!!
He was also constantly competing against his classmates, and obviously didnt see any consequences to his actions (no matter how much they were explained to him, and his choices for behaviour explained), think of the possibilites if there were no 'tomorrow'???
It was extremely hard, and still is (hes 15 and still home educated) but he is at last an ..interesting... chap to be with and much more thoughtful (tho still as impulsive!). We never went down the medication route, but i understand that some families find it a lifesaver. We have had to be really tough, (at one point he had nothing in his room but his bed - not even a lightbulb, he had to earn that back too!)but consistent behaviour management, reward systems and staying firm have eventually worked and its taken sooooooooooooooo long - but has definately worth it. Hes a pleasure to be with (even if his topic of conversation leaves a little to be desired - but if you are in the need of a 2hr lecture on pokemon , hey, hes your man... hey ho..)
Perhaps at this point your ds's behaviour will take a little while to modify... but i honestly believe that taking my DS out of school was the best thing for him, and the family, and for his future too.
Im sure there must be a service to help you, im sorry i dont know who (we were on our own back then), but services have improved.
Incidentally has anything changed at school to upset him? like change of routine/classroom/teacher?