In article , Tanya cornell writes:

I have a 16 year old cat whom I've adored for as many years. For the
past month or so he hasn't been grooming himself and has gotten really
nasty and dirty looking. He is an outside cat only because he wants to
be. We've tried to get him to come in but he refuses.
His sight and hearing are impaired his eating habits are good. Last
night I took some scissors and trimmed alot of mats out of his hair out
of despiration. He just lay there and let me do it and didn't move. I
think he actually liked it. I want to bathe him but fear him
scratching me or worse yet something happening to him since he is so
old and all. If anyone could tell me what to do I would be greatful.
And also why he won't clean himself.

Often when a cat stops grooming himself it's a symptom that he's sick. Take
the cat to the vet if you can.

Sharon