hi and welcome to our forum.....sorry your beautiful kitty is having some problems..I would also suggest you find away to get this kitty to a Vet, with the crying and drooling you mention IMO it is very likely a teeth problem. I will send you a link, but one thing they do not mention is FORL's which is very common in cats over 4 yrs of age, this is only seen by a dental xray and it is very painful...the tooth and root both need to be extracted if this is the case.
can you work out a payment plan with a Clinic? most will do this to help out a kitty in distress.
good luck keep us posted please...
http://www.sniksnak.com/cathealth/dental.html
Drooling is not uncommon, especially if a cat is purring. I once knew a cat whose name was Niagra because of how much he drooled. I don't know what to tell you about the loud breathing -- again, it could just be an idiosyncracy of the cat, or it might be a health issue. Siamese do have loud voices, so the calling all day long thing might again just be him, or it might be that he is in some kind of pain. Does he use the litter box properly?
In your shoes, I'd take a night job for the Christmas season and put together a handful of paper and get him to the vet, just to get your questions answered. That, or surrender him to the Humane Society. A cat as beautiful as a flamepoint should not have any trouble being adopted.
Good luck!!!!!