We went through this with our (then) nine year old Australian Terrier about four years ago. Our regular vet didn't have the resources to deal with it and Boomer spent two weeks at the local vet school.
He was extremely sick and the vets thought he probably would not make it. He did however pull through. He lived another two years when sadly lung cancer got him.
Everyday when I got off work I drove over to the vet school and spent time with him, the docs and the breeder who had given him to me felt that that had helped him to pull through. The first week or so was a roller coaster ride where he would do a little better one day then crash the next. I don't remember much about the "numbers" but do remember being told that some stuff was astronomically high.
You have some very tough and emotional decisions and times ahead of you, I wish you and your little friend the best. Good luck.
along with; Dixie, Angel, Dex, Leroy, Babygirl, Harley, Chubby, Jasper, Katie and ole buckethead; Samson
Women and cats will do as they please, and men and dogs should relax and get used to the idea. Robert A. Heinlein