I really dont know about the religious aspects of this whole thing but something I know for sure is that most people these days have their sons circumsized no matter what the religion. When I saw my newborn son....it was like REALLY ugly lol. (sorry, no offense intended, this is purely my own personal reaction). Its cleaner, its healthier and its MUCH more pleasing to look at so it should be done :)
No he doesn’t have to (if it’s difficult because of his age), if a non-circumcised man embraces Islam, he does not have to get circumcised if it creates any problems.