Both my girls are sick right now with colds and pretty bad coughs. ATM I don't have a cold mist humidifier but buying one tomorrow to put in their room.
My 3yr old is so sick she is back to napping so i do this routine before nap with her and again with both girls before bed.
I give Advil 45 minutes before bed and get them to have a few sips on hot(well warm) honey and lemon.
go into the bathroom and do a steam for 15 minutes.( they cough up lots of phlegm and their noses run like crazy during the steam and right after. I give them a big cold drink of water when we get out).
Come out and put vicks on soles on feet (wearing thin socks) chest and back
Jammies on
brush teeth
Put into bed with extra pillow under head so head is higher then chest
so tired from being sick they pass right out
Also if he is sick I would let him sleep when he want for how ever long he wants, bed is the best when your sick :)DD2 went for a nap at 2:30pm today cause she needed it slept for 45 minutes at still went to bed 1 hr early ( and is fast asleep right now).
HTH and hope he feels better soon.
i would also cut dairy products out for a bit to help with phlegm