Help with a sick (i think) corn!

[Bernice]

Ok... I have a 12 year old, male hypo charcoal corn thats busy scaring me...
He is getting skinnier because he is refusing to eat, today I noticed that he is sitting with his mouth slightly open and that makes me nervous of respiratory infection...

All the (hopefully relevant) info: its been HOT the last 2 weeks, as in 3o deg and over, i dont have air con, and im doing my best to prevent over heating, (computer fan over vent on one side to draw out hot air, on the hottest days I wrap an ice brick WELL in newspaper and put it in a shoe box so he has a place to cool down )
Hes also been on an intermittent hunger strike for almost a year now, hes starting to get skinny, but refuses food, he was never a fussy eater, but the last several months he will 'angry strike' at food but not latch on, or he'll 'kill' it but just not eat it... even when offered fuzzies or pinkies, my next step was to try braining pinkies to get him to eat.
But before I got him more pinkies i see him today for the first time sitting with his mouth slightly open... closes it and gets grumpy with me if I approach (this is normal, hes always been a little sh!t), so far no changes in his activity or attitude, just getting skinnier and the open mouth thing is new...

I guess what im asking is how flat of a panic should I be in? could he be opening his mouth because its hot? I dont see anything that looks like mouth rot and his breathing sounds ok, no crackling or wheezing that I can hear... any advice?