What is his relationship with his father? When early-teen boys start to act out, it can indicate that he needs a closer relationship with a male role model who shows him how to handle frustrations and other feelings that are welling up in adolescence. That's just a first guess. If there is a counselor at his school, it might be possible to arrange a consult with that person to look for specific issues that may be stirring him up. Feel free to write back about my GUESS, since I don't know anything about your family situation.
I agree that much of the time oppositional defiant behaviors tend to be due to an unmet emotional need. If there is s Big Brother program or mentor program I would suggest checking into that. Any kind of tea sports or even an individual sport such as jujitsu would be good for discipline and learning boundaries and how to balance emotions/ reactions.
I hope you have had the time to review and rate my response to your question. My desire is that if offered some sort of clarification! I do hope you will keep in contact. I would love to hear the progress. Best wishes and warm regards! Julie
And if you are in need of bibliographical references or suggestions, please just let me know! Thanks again, Julie