What sort of price range are you looking at? Most of the stuff from the big box stores are poor quality. Also need to know if you want a rifle/pistol for him.
Yeah guess we need to know what you mean by airsoft. To me, airsoft is the 6mm plastic BB shooting guns. But it could also mean pellet, metal BB variety.
The sky is the limit, as far as quality is concerned. Tokyo Marui builds accurate to life weight, with blowback, for about the price of an actual gun, but here's a pretty darn good selection of better quality stuff.