We used the American Humane Society guidelines for slowly introducing Pascal to our other cats, Jasmine and Cooper.
For the last month or so Pascal and Cooper have been sparring nightly. They are both quiet when they do this and it seems to be fun for them. They seem evenly matched.
Pascal has been to the vet now for a checkup since we noticed he drinks a lot of water and he is losing more fur. Turns out he is in the initial phase of kidney failure (common in elderly cats). We're managing this by switching him to high-protein wet food which is easier for cats to get moisture from -- plain water just goes through their system and stresses the kidneys. He's also on cod liver oil, Chinese herbs, and acupuncture! Our friend Lena, a veterinary acupuncturist, has been helping us with this.
To help with Pascal's new diet I made a cat feeding box for him so Cooper wouldn't end up eating all his food. Pascal is also used to eating whenever he wants and our feeding schedule for the other cats was something he wasn't so happy with. The feeding box (which Jennifer calls the "food hut") has a locking door that is unlocked with a magnet on Pascal's cat collar. Since he had used a cat door previously he started using the feeding box the first night.
(Large storage bin from Storables.)
(Cooper ponders how to get the food.)
We got an additional, shorter cat tree from our friend Julie, and Pascal seems to have adopted it. He also likes sitting in our bedroom window on warm days, although we have to lift him up there.