As someone who has also taken a lot of graduate level math and taught myself on my own other areas of math and computers, I second Austin's suggestion. The introduction to statistics at the college level was awful. I stopped taking math for a few years after that. There were no proofs or intuitive ideas presented--just memorize this and compute that with no theory behind it. My graduate courses in probability and statistics allowed for a much deeper understanding and discovery of relationships. There are also other good mathematics courses at the college level that would probably be accessible after calculus--abstract algebra, differential geometry...--that do offer this depth and exploratory aspect to students.
Computing, on the other hand, might offer some abstract ideas to test out on his own and some practical application to his projects. It is much easier to see what is being done and why it is being done than an overview of statistics.
