One of foosball's biggest problems is the fact that most of the serious venues are bars. At it's peak, most of the venues were arcades. We've lost our ability to showcase the game to the young ones.
Hopefully, some of the St Louis players will respond and point you in the right direction.
The weekend of July 3-7, there will be a large tournament at the Sheraton Westport Chalet Hotel, 191 Westport Plaza, Maryland Heights MO 63146. This will be a good opportunity to see some world class players. Your son should be able to play in the beginner class, but be forewarned...there are a lot of "beginners" who are not beginners.
I'm sure he'll like it. One of St Louis' best players was about 14-16 when he started dominating. That gives your son a 6 year head start.
Here is the link to the schedule.
http://foosball.com/schedule/index.htm