A few thoughts here -- DH has a younger brother who is 17, who is adopted with stuggles similar to yours OP. He is Bi-Polar with RAD and learning disabilities and is on meds.
1. Has he had a full psychiatric work up? I know you mentioned ADD and ODD, but do you think the ODD could be mistaken for RAD (reactive attachment disorder?)
2. How does he relate to others? How do his teammates view him? Does he have a pretty regular social life outside of team sports?
From what I've learned, sometimes the family gets the
worst of the behavior especially the mother. Kids with RAD cannot "attach" themselves to the family and home environment. They constantly have theiir guard up due to unpredicability in their lives. Now that you have given that to him, it is
scary and
unknown. His was of stealing is protecting that little bit of "freedom" (lack of a better word) he once had.
I think there could be many many different things going on and the earlier you figure it out the better, so he doesn't become involved criminally with the courts. (We have already been there! The courts didn't know what to do with him, they're overcrowded and the best thing is to KEEP HIM OUT!

)
Major

to you OP! My brother in law is now out of the home and being treated at an inpatient facility. It took many many years of confusion, exhaustion, and stress to finally sort of put the pieces together. Will he ever be able to move home? We don't know at this point and most likely probably not.