I absolutely do agree that adding the dog when times are rough was a not-fabulous idea. So now money is going towards a dog that could be helping this cat.
But I do also think there was some unnecessary roughness about the cat. I had plenty of money to take care of my one cat when I got him -- later when times were tough and I was barely feeding him is when he ended up with diabetes. And yes, I avoided going to the vet due to lack of money. (Not realizing what this was doing to my cat.) And no way in hell was I going to just give up a cat I'd had for 10 years and had a very strong bond with - be like giving up my kid. Especially, as J said, for a temporary set-back. In the long run, we did get him treatment, I learned a lot out of it, he lived 5 more years, and died of cancer. (And had enough problems that fortunately I was able to later afford it all.)
I also feel pretty strongly that if all someone can do is provide the basics, that with all the millions of animals we have killed every year, that one is better being in a loving home than just being euthanized with no chance at life. (Although the key word there is "loving" home and there is a line to be crossed where I think they're better off being euthanized.)
And no I don't mind the repetition of slowly and carefully in the side of the mouth. I tried to to italicize that point - maybe I should've bolded and underlined it, cause I do know where you're coming from.