Virtually any Tippmann or Spider will do....I have even heard good things about the JABB Pirahnas. I say take him into your local Pro Shop (if you are lucky enough to have one nearby) or WalMart and let him handle a couple and see what fits him the best. Comfort can be a big deal with a marker, especially for a younger player, and a lot of modern markers seem to be designed for bigger hands. I would recommend staying away from anything but jabbs for awhile....a lot of people swear by markers others say are finicky (I'm looking at you Mags and Cockers) but if a jabb goes down it is virtually always just an o-ring away from being fixed. Simple = better for beginners, and it doesn't get much simpler than jabbs.