My 15 yr old neutered male short-hair grey tabby mixed breed, Zydeco, refuses to eat wet food, nor even semi-moist. He's getting so thin on even good quality kibble! He's always been a slender but athletic guy, but I now see his muscle mass vanishing and his coat not glossy as it was. He drinks and urinates well. His bowels seem fine. He does vomit more than h did before, and no hairballs are seen. He's less active than he was a younger cat, but still seems interested in the world and communicates well with his family. He is not as strong but still vital. He has all his life been on free-feed dry kibble, and has a conniption fit is his bowl is getting low. If he can see the bottom of the bowl, he won't let you alone.
He's never in his life (he was born in my closet) shown ANY interest in: wet dog or cat food, semi-moist dog or cat food , raw foods, people foods like tuna (canned or fresh raw or cooked), chicken, fish (freshwater, salt water, aquarium), ice cream, cow's milk/cream/cheeses, goat milk/cheeses, beef, lamb, goat, pork, turkey, bacon, rabbit, cuy (guinea pig meat), pigeon/squab, ostrich, wild boar, venison, emu, kangaroo, alligator, rattlesnake, nutria, crane, mink, turtle, shrimp, crab, clams, mussels, conch, octopus, squid, geoduck, uni, eel. He HAS eaten self-procured insects and lawn grass. He rubs and nibbles catnip and eats cat mint a bit. He shown no interest on cooked vegetable, and not in raw ones either, except a few tastes once of sprouts and micro-greens, never since. He sniffs anything presented, then moves on. He went from the teat to kibble and I have never found a treat from a bag or a plate that he found worth eating.
What can I feed this dear friend? I don't want to watch him waste away! He likes MeowMix, Friskies, even cheap/crappy kibble. Have had him balk at "good quality" kibble like Iams, etc. He has always eventually eaten it, but notably less desirable in his eyes. Suggestions? I can't get him regulated if I can't get him to eat.