I’m so sorry for your loss and I understand what you’re going through as I lost my best friend last year after almost 17 years. My vet was the same in that they pushed me to try everything despite his advanced age. I had the money so I did it but we lost him anyway and ended up with a $4000 bill. I wish the vet had been more realistic but they are sadly in it for the money and it was most likely this which was behind your vets disapproval. Your cat was well loved and you’re definitely not a bad pet parent. You probably saved your baby needless suffering and yourself a big chunk of cash.