I think the best way to go about learning, especially because he is young, would be to have something that he wants to build and then to learn what he needs to

I think the best way to go about learning, especially because he is young, would be to have something that he wants to build and then to learn what he needs to do it. Maybe a game, a facebook app, a chatbot, or if he has an idea for a web app he thinks would be cool. Python is a great place to start, and learning HTML/CSS is a really good idea too. Because he already knows a little Python, Google App Engine might be a good place to start because they have good docs, it is relatively simple, and hosting will be free.