FloridaHokie, You state, "He's being actively recruited by several major-conference D-1 programs in the southeast." If true, and there's no reason to doubt you, then he is already on the "map" and other schools know about him as well. His GPA puts him way ahead of others with equal talent and lesser academic qualifications.
Your problem as I see it is not getting a baseball scholarship, but trying to keep your son from getting discouraged by playing behind a senior with equal or better talent. NO ONE wants to sit the bench. The question I have is, is your team THAT strong that a player of your son's talent couldn't move to another position for this year only? Strong arm, good bat, good attitude, good size-there are not too many teams(actually none) in the Orlando area that he would not start at with those attributes and I and have also seen top teams from all over the state this past week that he would be welcome on as well. Third base, first, right field???
Have him go to the coach and say, " Do you think I could help the team by playing another position for now? I know ----- is a senior and earned his spot, I just feel I could really help us this year."
I don't think the coach would be offended and actually may appreciate a kid coming forth and letting the coach know he will do anything the team needs. Nothing to lose. IMO
Good luck.