Bone Cancer In Dogs

First of all, the old bastard is almost 17 years old. He was always an outdoor cat, and other cats always seemed to really respect him. We used to call him “The Godfather” and “Satan” among other goofy names. His real name is Milo (like from the movie, I think it came out the year he was born…1992?).

I was away at school and returned home to my parents (who keep Milo), and a few things were really odd.

We have a Black Labrador that he always hated. Milo got the front porch and Angus got the back yard. When I was sitting in the back yard with Mom and Dad, Milo jumped over the gate (barely) and walked up to Angus, and the dog LICKS him. Mom says recently the dog and cat have been hanging out. The dog is 11. So after 11 years they call a truce? Okay, so…

Then I go over to pet Milo. He always had kind of a thick black and white coat (a tuxedo cat), and when I stroked his fur, it was as if he was just fur and bones! I could easily feel his defined cheek bones and he rubbed his face on my hand!

“What the hell, Mom!!”

Mom says he eats plenty. After that she gives him a whole can of wet food, which he then proceeds to eat all of. She guessed stomach worms; I guessed cancer.

I swear he’s barely over the size of a kitten, and you could have guessed it if it weren’t for his rugged appearance (the end of his ear is split at the end, I guess from some fight probably ten years ago or so). I guess he weighs about 3-4 lbs. And he just acts like he’s stoned all the time. I know he’s old, and probably will die within the next couple years, but I love my cat and want to do something to help him. Can anyone help?
Awesome answers so far guys, thanks so much.

Here’s an addition to the question:

We live in Houston and our house got pretty screwed up in the hurricane (RIGHT after some really expensive renovations), and I don’t see my parents allotting too much cash right now to treating the super old cat. He hasn’t been to the vet in a while, mainly because he was so wild and getting him in a carrier would have been close to impossible. Nowadays I think this would be pretty easy.

I was thinking of personally funding Milo’s treatment, and I was wondering (ballpark) how much a diagnosis and treatment of Hyperthyroidism would cost?