I am sorry to hear that. It is a tough thing you are facing, and as you said, you have tried out everything.
It looks like he is angry about something, or angry with someone deep down. Maybe he is finding it tough to cope with the studies or the way things are taught at school.
Talk to him and ask if there is anything or anyone who bothers him. Assure him that you are on his side.
Changing behaviour takes a long time, but identifying the problem is the key here. I know you have tried counselling, but if you can talk to a Psychiatrist who specialises on childhood behavioural issues, it might help you out. All the best sister.