Python is a good choice because it is clean, easy to learn, and has a large choice of libraries like pygame. It is important to choose a language that encourages good programming practices. For that reason PHP and Basic are bad choices. Some of the worst code in the world is written in PHP or Basic. I would also stay away from languages like perl.

Avoid languages like C++ or Java because there is so much to learn before you can produce a simple Hello World. There is no reason to learn OOP to do a simple task.

I think JavaScript would be a reasonable second language. He should learn programming firs before having to deal with browsers, the DOM model, and OOP.