If your toddler is sick do you let them sleep when they want?

T has a nasty cold (low fever yesterday). He was up a few times last night coughing (and coughed so hard he puked all over his bed). It's 9 am and he's still sleeping. He's usually up at 7 and has nap at 1. I'm just letting him sleep, I guess! When would you attempt nap? A little later than normal but not much later so he goes to bed on time at 730/8? (He is 17 months).