Richy, I feel for you on that, I truly do.
We have our oldest, (out of 5 cats) Felix, who I call "My Familiar" due to his choosing me, as his human,(although I love all our animals, the 5 cats, the dog, chinchilla, & the bird equal) that's right around that same age. He's been dropping weight like hell, & sleeping more like a crackhead after a month long binge....daily...
I know he's soon to be on his way out, and I do NOT look forward to that day.