It may or may not help him with his first tour choice...needs of the Navy will always prevail.
It will ensure that he doesn't need a waiver to get an instructor tour later if he so desires (reenlists). It may help him out with an officer package later.
Beyond that, his job is just beginning. His scores will all but be forgotten when he gets to the ship/sub. He starts from scratch there, and they could honestly care less if he was first or last, as long as he qualifies on-time or early and contributes to his division/department/ship/sub.
As far as civilian stuff goes, I am inclined to say that no one really cares about school scores. I am in the job market now and I have not yet been asked my class standing, and I can hardly remember it anymore.
Good on him, though. It's a nice accomplishment.