it sounds like he was fine with the water wings. I'm sure he learned a lot from that incident. I'd leave it alone. Or offer to get a little pool he can fill his bucket from for the back yard.
I was a lifeguard for many years, and a swim instructor. Water wings were not allowed at any pool that I worked at. This was b/c they can slip from the childs shoulders to their wrists, and then the childs hands are floating but their upper body isn't - so neither is there head.
I rescued a child once who was wearing water wings - they had slipped up to her wrists, and she couldn't get them off, and also couldn't pull her head above water. It was very scary for her and me, and her parents felt terrible. I would not use water wings.