As you stated, it is very far out to see all the "good" stuff in the snorkeling lagoon. There is also some waves, usually mild, wind, and a small current. You are not allowed to bring rafts or noodles into the snorkeling lagoon. If your son has a problem with endurance or has never snorkeled before, I would re-think the journey out to the statues etc. The vests do inflate and help with staying buoyant, but are not PFD. Just be mindful about not getting into a situation where he gets very tired and you have to tow him back etc.