In Orlando itself you're a little limited as the beach is an hours drive.
Snorkling, the "shark reef" at Typhoon Lagoon is a great option. He can go as many times as he wants and there is no cost to it.
I doubt you'll find wind surfing unless you go to the coast, but WetnWild have a wake boarding course. I haven't done it so I don't know how it works, what the cost is or if there are limitations
Here's a link to the "kneeskiing" at WetnWild that I am talking about. Info is not really forthcoming http://www.wetnwild.com/Orlando/Main/Main.asp?ContentID=7&CategoryId=4&SubCategoryId=1