Is he sleeping? Is he dead? What to do??

Small Boy has been napping for 90 minutes. Small Boy never naps for 90 minutes when not in a moving vehicle, and sometimes not even then. Do I go in and make sure he's breathing and risk waking him up out of this blissful nap during which I'm actually getting stuff done? Or do I assume he's alive because really, what are the odds that something's actually wrong, and keep getting stuff done? He's fine, right? Right?

Edited to add: You know I went and checked. Small Boy lives. And sleeps.