Is his nose draining..yucky snot? I know for anyone, no matter the age, this is what can make the throat so sore! That gunk drains down the back of your throat as well (its just one big super highway in there...nose, throat and ears..why do you think those are the specialty docs? ENT's are Ear, Nose and Throat Docs! :-).
Drainage is usally the worst when sleeping/laying down..so naps and night sleeping. The gunk drains and we wake up raw and sore and sounding all rough, not wanting to eat..whiny and grumpy in a toddlers case, perhaps? Cold food should feel pretty good...warm as well, as someone else suggested the warm teas in a sippy (to his temp). I always did that with my daughter and since we are a tea household anyways (hot and cold), she is an AVID maniacal tea drinker now as a teen! But cold popcicle (make your own from watered juice if you like), or some warm tea? No reason you can't.
After 14 years running my own Home Childcare...I can tell you temp of food (and baby bottles) is totally a preference thing. And for me...I do not feed baby food to one year olds (not sure if you meant YOU are or the daycare is). Just me. Most of mine are not eating it well before that. But I can say as far as fruit, etc..most prefer more of a room temp thing. But I feed a few cold things like meat for sandwiches, cheese...stuff like that (that was todays lunch...11 month old and just turned 1 year old yesterday had a sandwich just like big kids...cubed up...I use my pizza cutter to cut everything like that..works great!).
I was always for making my child comfortable..at least so she could sleep as it made a world of difference in her dispostion. My Dr was never opposed so stringently to meds. He told me the dose for her weight of the proper OTC decongestant to attempt to dry up the snot production over night so she could breathe easier and rest and not wake up so sore in the throat. I was all for it. I rarely did that in the day time..better to let the cold run its course...but I like to be comfortable and breathe when I sleep with a cold...I did the same for my child. It did not negatively affect her long term in any way. She is 16 now.