I think I have read that approximately 2/3 of FSU's players attended their camp at one time or another; which, as Tallydad suggests, doesn't necessarily mean that they were discovered at their camp. Surely, some of them were seen elsewhere first and encouraged by one or more of the coaches to attend. In instances such as those, the camp ends up being an excellent way for both player and coaches to get to know one another; both on and off the field.
As I imagine you know, you certainly live in the right state to attract their attention. A quick scan of this year's roster indicates that only about 6 of their players came from outside Florida; mostly from nearby Georgia. Given the high quality of both scholastic baseball in Florida and the Florida State program, it stands to reason that it would be that way.
Given the fine man and coach that I know Mike Martin to be, it's a virtual certainty that he'll leave his excellent program in good hands when he decides to step down; and, it's hard to imagine him not having a lot of influence on the decision.
Best of luck to your son!