Getting started with robotics
See if there's a FIRST team at his high school. They're a great place to start learning about robotics and he'll get to actually make stuff. If not, something like a Lego NXT kit or Vex kit would be a good place to start. They've both got pretty easy methods of programming, and since they have pieces you put together, you don't need to worry about machining your own parts. That way he can concentrate on getting something actually working and driving around instead of designing electronics, fixing tough programming bugs, buying stock and milling parts.