I think that others have pretty much answered your question and I think that you have nothing to be worried about. I suggest having an eval done with the best neuro psyhologist or neuro psychiatrist that you can find. They do very extensive tests instead of just asking a few questions and then giving a DX. I suggest that type of eval because of the grades considering what his IQ is and other things that you mentoned. I also think that you should take him to a therapist. If you have an eval done like I mentioned he won't have to keep following up with them, they would just say what is going on, what they think the cause is, what needs to be done, and where.