Dreaming in code isn't that weird. Given that sleep is your minds way of organizing the previous days experiences (amongst other things), it's only to be expected that you would dream about whatever took the majority of mental time while awake. For most kids that would be playing with their friends. For adults that might be stresses of their day to day life. And for people who spend most of their waking life coding, we're inevitably going to dream about coding.

That said, when I was at college and would spend 2 or 3 days coding for about 18hrs a day, I would have the weirdest dreams that would resemble the scene from The Matrix where Neo first discovers his power. Except rather than green text on black, it would be the syntax highlighting colors that my (then) IDE defaulted to.

Going back on topic though, as normal as the "dreams in code" thing is. This kid clearly still has a natural talent and the enjoyment of the subject to push himself further. So best of luck to him - not that I think he'll need it.