He seems to drink a lot of water. I’ve been considering one of those fountain bowls.
I had two Maine Coon kittehs, brothers who lived for 14 and 16 years respectively. I advise keeping a hairbrush handy, and brushing them whenever they stop by to “visit”. Not all cats like to be combed, but they all seem to like a soft human hair brush. Short hairs generate a respectable amount of hair, too.
This will 1)cut down on what they swallow 2)cut down on hair matting 3)cut down on hair floating around your house, all good things!
I recommend feeding meat-based canned food. Dry foods containing grains (and rice is a grain) contain levels of carbohydrates kittehs are not engineered to handle, and predispose them to develop diabetes. Read the labels. Avoid “gravy” formulas.
Canned food has another advantage—it contains water, and cats rarely drink enough water. If your cat begins to drink LOTS and lots of water, it is an indication that something has probably gone wrong.
Drinking a lot of water indicates something may be wrong. Could you ask your vet to do a blood panel, if you haven’t already done so?
If you do get the water fountain, get a metal one. The plastic ones forms a “slime”.