When do the cramp occur, post workout? Is it a reaccuring thing(like every morning or something), or do they pop up sporadically?
Sounds like he might have an electrolyte deficiancy, he could try adding potassiam(sp?) and if he doesn't get enough, sodium. This used to happen to me in muscles that weren't fully developed. When they weren't used to the strain hard training puts on them, they tend to cramp after a workout when cooling off. This could be the case with your buddy. Most likely it's a combo of a number of factors, and he'll just have to test some things out and finds what works for him.