S.M.
From the Coconut Creek area I'd recommend the Boca YMCA (off Palmetto Park just east of Powerline), esp. for a 5-year old (for 3 and under, I like the way LifeStyle teaches and they're definitely worth the drive to FAU).
The Y has classes from 'not-quite-able-to-swim-on-their-own' to competitive AAU swim team, and you can take the classes during the week or on the weekend. They also have a pretty cool waterslide that they won't let the kids use until they can swim an olympic lap, which is a nice carrot for a boy that age.