You can also give him Baby Benadryl to help dry up his snot and it will also let him sleep.
Using some baby Vics rub on his chest too will help. And I stand by a warm mist vaporizer works better then the cold in these instances, but that might just be me.
My daughter is 1 right now and is also sick and it's so hard-I know!
Since he's already on meds your big concern should be dehydration. If he's at least taking fluids you are good-don't worry if he's not eating.
Also-give him yogurt juice or yogurt or a probiotic, etc to help off set the antib issues that he's going to have with his system.