His eye contact isn't great even w/ us. He makes good eye contact when he is listening to someone talk but when he talks he tends to make eye contact for only a couple seconds at a time.

But yes, he has mentioned that the kids in his class don't understand his jokes. He knows not to talk about certain subjects (like history) because they don't care and don't get it. On the one hand I'm glad he's no longer babbling about topics that no one else cares about, but on the other hand it makes me sad.

I'm pretty sure the teachers in the school all think he has Aspergers or something similar, just because of the more superficial characteristics like his voice, eye contact, how he says he has no friends, etc. I wish we could just rule it out once and for all rather than people wondering about it if that's not actually the issue.