Actually, I don't think he would lose his passion in math just because you can't teach him. What I have seen of high ability math kids in our area is that they drive themselves much of the way. However, it would be helpful if you can get him into some kind of local math circle or math club and involve in some elementary or early middle school math competitions. At that age and level, I would encourage depth rather than speeding through basic curriculum like Khan Academy. Try logic puzzles and games. There was a website with books (the Critical Thinking Company?) that aim for developing critical thinking skills but I hadn't purchase anything in about five years.
