Mental rigor of programs is important. Computer Science gives a rigorous preparation to think well. Coop programs are good to transition from academic to work settings. Math background is invaluable, the harder the better. He particularly got a lot out of probability.
Any classes oriented to data like database design, theory, concepts, accessing are important.
Have hands on work in the curriculum. The specific applications and technology will change but exposure to current technology is necessary. He learned how to learn. For example database work with XML and Java. Also participate in a coop program.