steven, I think Grey hair is attractive -- and there isnt anything wrong with it- Heck, I think it's sexy on many guys!
It's just good to look into anything that may be triggering premature grey hair -- just in case it could be an underlying sign of something in the body that needs correcting.
Prevention is the best cure.
If he tries everything suggested- and has a healthy diet- and a good outlet for stress- then at least he can breathe easy that nothing is wrong healthwise- and it probably is just some gene from a distant ancestor.