I don't know if creatine would be good for him, unless he uses it during a certain length of time where weight-cutting isn't a factor.
The lack of water, during weight-cutting, could mess him up (At the very least, make him feel weak due to resulting diarrhea, which happened to Shane Mosley before a fight).
I remember reading a lot of stories about amateur wrestlers dying due to the extreme weight-cuts and using creatine at the same time. I assumed the stories were legit, and not typical fabricated media BS, but I never really looked into it. It seemed to make sense, on account of the amount of water needed when using creatine.
And, this is a no-brainer, but if he's still in boxing by the time he's in his 20s, and decides to use roids, he'll have to do it in a way to pass roid tests. Also, this is a slight bit on the paranoid side, but he should probably take any pics of himself off this site which show his face.