Finding an 8 speed hub is going to be a pain, but he can get a 9/10 speed hub and get a spacing kit for 8 speed. Write up is here: http://www.branfordbike.com/campy/campy.html

Mavic Ksyriums are bomb proof, especially for big guys. Find them used and he will be good to go. If, though, his stock wheels happen to be 32 spoke wheels, he can probably get them rebuilt so they will be strong enough to handle the weight. I did that with one of mine that was too flexy - worked out well.