So sad to see your cat sick or suffer, a real dark cloud living in the shadow of sickness.
(my mil going on 10 years of Alzheimers seems to have conditioned me.)
My wife and I had a deal for the last 20 years.
Every time I got a car she got a cat.
After we got up to 5 indoor cats I stopped buying cars! lol
4 of the cats have been healthy and maintenance free.
Cosmo the white indoor cat has had 3 big issues.
At 2 years old got an eraser stuck in his intestine.
Surgery was successful to remove the intestine and eraser, Cosmo recovered.
Look no teeth, still has his claws.

at 7 years old he suffered for 2 years with red inflamed gums, he had Stomatitis.
A gum inflamation that lives in the roots of the teeth.
We took him to our Vet and they removed all his teeth.
Unfortunately the Dr left a few roots so the Stomatitis continued.
An xray indicated some roots still remained so went to a cat surgery specialist that dug deeper and got all the roots of the teeth out.
Months later the dental work healed and the Stomatitis disappeared.

At 13 years old, 5 months ago he was diagnosed with slow growing cancer in his intestine.
That's where we are now.
He had a feeding tube for 2 months that we fed him gruel, water and meds.
The tube is out and he seems happy and we pill him once a day with Prednisone.
Anti inflammatory for his intestines, seems to be working for now.
We got one order of Kemo to treat the cancer but I could not give Cosmo Kemo.
I didn't want to see him suffer the negative affects of Kemo.
Today Cosmo and Max the black cat doing well.