How do I coax the guy I like to go to a water park with me if he has had a near drowning experience at one?

Ok, so there is this guy that i REALLY like and I went to a water park yesterday and the tickets they sold were "buy one get two entrees." My sisters went with me and they did not wish to go back, I however, did. I came up with this crazy to ask him to tag along with me. We are friends, but I want to be more. At first, I want it to appear like a thing friends would go to together, but then later on, get to know him better personally. When I asked him, he told me that when he was a little boy, he had a near drowning experience that almost resulted in his death. Now, he is around 10 years older and is a swimmer on our school's swim team. (Ironic? Tell me about it) I want to try and talk him into going with me before the summer break is over. How do I go about asking him to go without coming off too strong? I am CPR certified and told him that we can skip the lazy river (the one he almost drowned on)