BigQ,
In short, your son has strong academic numbers. He should be communicating that right now to the schools he is interested in. It wouldn't hurt to have some flyers/resumes/one-pagers at the events to hand out to those schools he has not communicated with already. As others have suggested, follow up with these coaches after the event.
The coaches have to see him play to know he is a fit for their program and baseball level. just as your son scored a 32 ACT (thereby seperating himself from many others) , the coaches need to see him run, throw, hit, pitch to meet an athletic metric. If he does, they may convey their interest. It never hurts your son to convey his interest in the school at all times. In summary, that is the game you are playing.....it is all about the numbers. For high academic kids that want to play college baseball, you have to have both sets of numbers.
Good luck!