Hi sk8er, welcome to CruiseReviews! I think your son will be dressed just fine. If you're going on a warm itinerary, he might consider some shorts, too. Of course, he'll need a bathing suit for the pools, slides, and hot tubs
I'm glad he likes to wear clothes that fit and not hanging down around his knees
He's going to have a great time. They have a fantastic program for teens and I'll bet he'd find some kids around his own age to have fun with. I know he'll enjoy being able to eat good burgers, dogs, pizza, and ice cream. Of course, they have other great selections, but they even have fries now.
I hope y'all have a marvelous time!