Kids this brilliant will go straight through to PhD - and more than one, especially if, like you said, he's thirteen the first time through. And if he's that smart, he'll end up in research which doesn't necessarily have an age limit (which, for a kid like this, will probably just be fun).

He plays with kids in martial arts, and I imagine his parents, who also have high-level degrees, are very aware of the difficult balance of letting him learn everything he wants to, developing important social skills, AND taking time off for fun. Look at the smile on his face - he's not being pushed. Did you read how Mom had to learn how to teach him differently? He blew her mind, too. Kids that smart are just plain going to have a certain level of social ineptitude. A friend of mine stayed in high school while taking college classes, but it didn't help his social skills at all.

I love that you care so much about a complete stranger. Never lose that.