How old is he? I DO NOT recommend hamsters or guinea pigs to anyone under the age of 10. Hamsters have the tendacy to bite, and children sometimes can't quite grasp the concept to not to mess with the hamster. And with guinea pigs.. their legs are so short, if they fall even a short distance they can break their back and be paralyzed or die.

And whoever said gerbils bite??? That's not true. They bite MUCH less than hamsters! I recommend a gerbil over a hamster for kids because they are much less prone to biting, but they are FAST!!!

A turtle or tortoise is a good choice (there IS a difference! Tortoise = primarily land dwelling; turtle = primarily water dwelling) but as you said he is afraid of them, so you don't want to get him something he is afraid of.

What about a bird?