Old cats and dogs, like old people, do suffer from stiff joints. I am sure there are medications you can get from your vet. I like to use Flexicose for Pets. I usually buy mine on Ebay. For a small cat, one bottle lasts nearly a year. Since it is liquid, you can sprinkle it on his food. My...
My cat Callie is 17 years old and has exhibited the same things your cat has, and more. My cat is experiencing dimentia and/or alzheimers. Her yowling in the middle of the night lasted about a year but has now passed. You may next observe stumpy staring at a wall for hours or falling asleep...