Since he is still fairly young, my first guess too would be illness. He needs to go to the vet. If he were old it might be just his age, but even then a vet visit would be warranted to rule out illness. Cats are naturally fastidious, so when they aren't it means something is wrong.

Realize, too, that in nature an ill animal is a doomed animal, so cats also naturally hide that they aren't feeling well. So this kitty's parents might assume nothing is wrong since he's not acting sick. It may be that he is acting well and his dingy coat is giving him away.

[ December 15, 2001: Message edited by: Leah S ]