If he's certified, he can go over to SeaWorld and spend some time in the shark tank.
They put you in a steel shark cage that takes a slow 25 minute trip through the big tank filled with sharks, that part of the Shark Encounter attraction.
My Dh is going to Ginnie Springs during our May/June trip. He found a partner on the Scuba discussion boards. It's a couple of hours away, but it's supposed to be one of the best places in FL. Hope it's OK to post a link. Diana