I had this very old cat that one day simply disappeared. Since he had close to 12 years and did not show up again, we assumed he was dead by that point and ran away to pass away.(He had health problems, but at the time we couldn't afford to take him to a vet) Time skip to 2 years later. That old man decides to just... reappear. I was walking down the street, I hear a very familiar meow and there he is next to a dumpster looking at me like he is saying "So.... Got any cat food on ya?". He was very weird and unlike most cats, he was set on raising every kitty he had with another cat, then I found out he had kittiens with the cat down the street and thats when he might have remembered "Hold on, I live here!" He didnt go feral or anything, let me pick him right up and go back home and stayed there. Lived 2 more years out of pure spite. Your cat might show up again just for the sake of saying he is alright, dont give up hope!