I do this stuff for a living.
If he really wants to "learn" how the camera works, go with something like a K1000 or a Nikon FM. They are truly great manual operation cameras. He will learn the relationship between shutters and aperatures.
However, you can get the same functionality on some of the mid level digital cameras. The immediate feedback and ability to shoot literally thousands of pictures without having to go into the darkroom is a great thing.
Digital imaging has changed the photography world. I can easily say that my film cameras havent come out of the cabinet for almost a year. Everything I do is digital. However, going digital means using a PC or MAC a lot. The overall start up cost can be significant.
Private email me if you need more info or want to bounce ideas.