I don't have the link here, but there are two kinds of phimosis. One is GOOD. It's called infantile phimosis and it's supposed to be that way. The normal infant foreskin does NOT RETRACT = phimosis, see?
Pathological phimosis happens years and years later and is caused by forced retraction in the infant and preretractile period. That is BAD.
In other words, I can say with complete confidence that he doesn't have a thing wrong with him, phimosis-wise!
Don't try to pull his foreskin back, even a little bit - it needs to stay right where it is until he fools with it or it comes away on it's own.