Tips for palliative care of aging cat?

I had a cat not long ago who lived to be 19 years old and she developed kidney and thyroid problems at 14 years. We started with meds, but she didn't react to them well, so we discontinued them. She would eat the most unusual things in her senior days, and I didn't worry about it being typically healthy or not. She was offered everything and denied nothing if she ate it. She even opened a fruit cake one year and ate half of it. I figure she knew more about here dietary needs than I did. Your geriatric cat will get some nutrition from whatever you feed her and from whatever she wants, so don't hold back. She won't absorb the nutrition the same as in her younger days and there isn't a whole lot you can do about it...even feeding her the most nutritious food will not make much difference. You might find that her water intake will increase dramatically, so make sure she has lots of fresh water available. Eventually, she will dehydrate because the water will seive through without her body absorbing much, and it was at that point that we decided there was no quality in life for our cat and had her put to sleep. The vet determined that she was probably thirsty constantly and weak and would not be comfortable. She lost most of her fur and she was a Maine Coone with lots of fur and the full ruff all her younger days. She lost a lot of weight, going from 14 lb. down to just over 7 lb. in six months, and there isn't much you can do about that. It is difficult to determine when the right time is to let go, but after the experience, I realize I wanted her to live forever and probably allowed her to live longer than she should have. I am now living with that regret, so I advise you yze and reyze daily to make sure you do the best thing. So, in conclusion I guess there is no way to determine what "the best" diet is for this condition, so don't focus too much on it....let her have her way in her final years and be content that you have done the right thing.