There's a lot of fun in the idea of "gotta get them all" so I understand the drive. Like AnneE said, priorities may shift over time. Tell him that you absolutely will support him. Then start with the ones he really loves. If his interest changes over time, that's fine! It's how things go in life. He starts with motivation and then realizes his true goal is somewhere else, and that is quite ok.

Lisa Shea, Low Carb and Video Games Editor
Low Carb Forum