DS6 is a lot like your son. As a baby he met all of his physical milestones later but he learned to do the brain things faster. He's on the 5th session of level one swimming. Now they do expect a lot for level one but most get through in a couple times. He has a lot of water fear, it took most of the first session just to get him under. He loves it and has progressed each session, it's just progress is slow. He doesn't care one whit about what level he's in.
He's just now learning to ride a bike. He likes soccer and tee ball but he likes going more than playing. He ducks when a ball or frisbee comes his way

. He's not athletic at all. Of course we're not either so that didn't help.