Encourage him to take some classes online. If he has fun and then says he wants to be a professional programmer, your role is to honor and support that choice. Help him figure out which tools can be learned quickly and he can get paid for. Let him know it's okay to be slow. Help him when he's frustrated. Consider the possibility he may be using this as a way to know more about you.

Good luck to him and to you. He seems like a cool dude.