It could be vitiligo??? Google it and there are many articles about it. My girlfriend has it and the Doctor wants her to go see a Dermatologist and they put it under special light to help it go away.Is it all over his body or in certain spots?,my Girlfriend has it only on her Hands and Feet and it looks like there is no pigment. It seems to get worse in the summertime when her skin get more darker. You should go to your family doctor and let him have a look because I am sure that not being able to see the spots not to many people would be able to tell you exactly what the problem could be(Just be on the safe side)