My rescue cat, after ten months, is at "comfort" stage

So first off, I didn't get him at a rescue. I found him on craigslist last December, a family was downsizing.

My dog of 16 years had passed, and i love cats.

They had a barn & farm animals. He was in house basement w 3 other cats I'm told. He was 4 i was told.
Because of covid, i could not go into the house. The husband met me at the door with a pretty siamese boy.

I insisted he put him in my carrier in my car, as to not imprint on him, I was stealing him. It was dark. A long drive.
Once home my kitty turned out to be--emaciated, vomiting every food, major litter box issues, had fleas and worms. & permanently dialated pupils. (That part doesn't hurt, but does give him a doe-eyed look) I was shocked but launched into action.

He's my lucky charm tho, as I got an emailed job offer the next morning. After a lonnnng 2020 layoff.

A few vet appts w curbside drop off, revealed FIV, an infection, and he was much older like 8 or more. Meds ensued. Special food.
He bounced back great. But not much muscle development from his years of malnourishment. He's the most affectionate cat I've ever known. I named him Taishi after a Thai dessert.

He was diagnosed with a tumor on his kidney 2 weeks ago. Bloodwork revealed anemia, kidney issues, pancreatitis, high white cell count, and more. 5 meds. The hope was stablize so surgery could be considered. A long shot.

We cooked for him. He's an alert and strong-willed cat. But wasting. Last night he went into emergency hospital dehydrated & not eating.
They can't see surgery as a real option. He's coming home to comfort care mode. I've done sub cutaneous fluids with a cat in past. It may work for "a time", but not sure.

This cat purrs when held. He purred on way to vet. While waiting curbside in 40 degree weather last night for us to be let in, he purred. He purred on way home 2 weeks ago, after that visit. In his carrier! I'm stunned at this.

Such a hard luck story, for such a sweet cat. We are gutted.

Last friday, he made a trip up the stairs to my husband on his birthday. A few hours later my husband got a job offer in email.

Tell me we don't "find" our pets, or they don't find us. I'm convinced we do.

For however long we get, it's never enough. I feel robbed, I want more time.

But also am beyond lucky. A good luck charm found me, and blessed my life. But I'm just so saddened.