I don't see the point in being given top position. I want to EARN it. It sucks to be given top position and feel like everything you do is a mistake and you're about to be reversed any second (which you are).
I get a ''I gave him my precious black belt time, how impolite of him not to respect my ego'' vibe from the post too, which I don't like too much. Did you try to help him avoid the leg locks? To shut some holes in his game? Because that would have been helpful to him, and much more open-minded.
Either way, he's probably a fairly intelligent being, and BJJ is a self-correcting art. Either he'll adapt his technique, or move on to another one.