Um I dunno mate. My kids have always been shocking sleepers.
Dd2 is nearly the same age as your DS, sometimes she has an hours sleep, sometimes 2 hours during the day. I don't try to resettle, I just give her a bottle and some lunch and she is usually right to go and play.

She goes to bed at 7pm of a night time and wakes up halfway through the night and gets in with us. She doesn't want milk or anything, just snuggles.

She is getting her eye teeth though - is he?