My old guy is 23. Technically he is still good with the litter box because I have so many around as I also have 8 ferrets. So one in every room. His last bloodwork(4 m ago) came back within normal range for his age. However he is completely senile to the point that when he goes around the corner he is lost. As a result he caterwauls until someone comes to find him. And yes- this is day and night. He is skin over bone with dingy fur since he no longer grooms himself. We(hubby and I) do this for him with a damp warm cloth and a rubber static brush. He doesn't appear to have any real arthritic pain with his supplements.
He wants on a lap or snuggled close 24/7 if possible. He does appear to be mostly content when he isn't restless due to the senility.
I guess my question is- how do I tell when it is his time?