I'm sorry to hear about your cat. Honestly I doubt if there was much that could have been done. I had a girl (aged only 7) whose symptoms were just drinking a lot, not eating, and sleeping a lot more than usual. She went on a drip and then on medication and picked up dramatically but it cost about £500 by the time she had been hospitalised and all the tests had been done, and it only bought her about two months. It can be treated really aggressively but involves you putting subcutaneous fluids into the cat every night, expensive and probably difficult. I think your vet made the right decision.

Liz