The vet called a couple of hours ago. Advanced kidney disease can often cause ulcers in the stomach and mouth, and over the course of the night an ulcer had perforated his stomach. The only way to stop the internal bleeding would be an immediate blood transfusion and major surgery, but due to his age, the toxicity level in his blood (which was getting worse, not better), and the kidney failure itself, the surgery/anesthetic was guaranteed to kill him.
Left untreated, he would slowly and painfully bleed to death over the next 2-4 hours.
The only other option was to put him to sleep painlessly.
When I saw him I knew there was no real choice to make. He was too weak to even lift his head (but did manage an angry tail-tip-lash every time a dog barked in the next room). The vet gave him a mild sedative to numb any side effects of the actual shot... and that itself did it. There's no chance he would have survived even the start of general anesthesia much less the shock of surgery.
Thank you to everyone who donated and boosted the signal. The response was far greater than I'd even dared to hope. Thanks to you we were able to give him every possible fighting chance that veterinary medicine could provide. But sometimes that just isn't enough. I'm truly sorry that your charity and faith weren't better rewarded by the fates.
He will be buried next to his brother, wrapped in one of my shirts that smells like me and J's menthol muscle rub, his two favorite things to sniff in the world*.
I'm probably going to be offline/incommunicado for a while. If you see me online and say something and I don't answer, please don't be offended. Nothing personal, I may just be a silent observer of things for a while until I crawl back out of my own head.
Thank you again, to everyone and for everything.
* I made this and left it at the vet's to be put in his cage as soon as I found out he had to stay overnight or longer. The only thing that stopped me gfrom doing so the first instant was that they frown on getting topless in the vet's office. So I had to spend a night Sleeping In Clothes (which I hate but is WORTH IT), and cuddled up to J who randomly (ha) had minty. Which Raist always obsessively perched and purry-kneaded upon. I figured at the time it would be a Home Smell to comfort him. As it were, it ended up being a Final Smell. I'm glad I made the effort.