He should call Surf & Offshore and ask for Craig. 732-892-8303. It's a bit of a drive south of Manhattan in Point Pleasant, NJ, but Craig has everything. http://www.soswakeboard.com
He can also try Island Surf & Sail and ask for Terry. 609-597-4073. Terry's a little further south though, on Long Beach Island. http://www.islandsurf-sail.com
If he doesn't want to drive far, he can go to Boater's World in Paramus, NJ. 201-652-3595. This place has all kinds of watersports toys, including some wakeboards, but it's not a pro shop. The same guy selling wakeboards also sells rods, reels, hooks, coolers and vinyl stickers of fish jumping out of the water.