DS has lessons also and like AJP's DD, no was is he ready to swim on his own.. not a chance.

One thing they teach Jesse at swimming is.. sit them on the side of the pool.. cross YOUR arms (not theirs), hold their hands and as they fall into the pool untwist your arms so that they get use to turning their body around.. so in the case they fall in, they will hopefully automatically turn around and be on the wall of the pool, if you get what i mean. Another thing they teach is monkey crawling along the side of the pool. You just hold them (in the pool against the edge) and they use their hands to crawl along the side of the pool. Other things are just learning to kick and use their arms to paddle.

But maybe you can start lessons to start to get him more water aware?