It was a tumor between his stomach and lungs along with liquid intake nearing his lungs where it shouldn't be which over a month's period (could have been longer) caused his health to deteriorate and he lost weight pretty fast in that time, eventually he reached a point where he ate any sort of food and puked it up moments later which drove him to a point where he wanted food from you regardless of him puking it up. We had him checked and the scans showed the tumor, unfortunately he was 9 and in a not so great shape, having an operation would have killed him and I didn't really want to have that happen so I decided on the same day of the scans (he was still under after having them) to have him put down since the puking/tumor would have resulted in his death anyway. I dunno why but during that day we took him to the vets I had a weird feeling that he wasn't going to come back so I snapped some photos and gave him the longest hug I don't think I've ever given anyone, I think he knew once he was at the vets that he was going to go so he seemed calm and collect (some animals can smell or sense death with some vets).
That's so sad. =/ Hopefully he prefered to be put down than continuing like that. My cats are about 9 years soon. They were originally owned by our neighbours, but the cats kinda moved in with us on their own accord. Just ran in one day when they were kittens, and started coming back all the time, so we gave them food, and eventually they prefered to live here. We kinda had shared custody then. They could come and go as they pleased to our house, or theirs. Though they were with us for the most part. A while back, the original owners seemed like they were going to move. And one of my cats always wants to come into my bedroom, but I don't let him because he would jump on the bed and other places I prefer them to avoid after they roll around outside in sand boxes and stuff. But after hearing that, I let him in during the final days, and also took a lot of pictures and movies of him. Especially while he was in my bedroom and on my bed, where he's wanted to be for years.
Turns out though that only the mother was moving out, and not very far. About 5 minutes away from us. She did bring the cats with her, because supposedly her husband who still lives next to us, is allergic to cats. But the cats kept running back to us, and she said she came here and brought them back to her place about 10 times before giving up. Eventually, they asked us to fully take care of the cats, because she was moving, again, but much further away, and her ex husband was supposedly allergic. So they're ours now. I don't really know how often you're supposed to take them to the vet for a checkup though, but after hearing your story, I should look into it more properly. =/ Right now they seem fine, except they're afraid to go out due to all the fireworks. So for the first time ever, one of them have peed inside of our house. They're nice cats though, and I like to go for walks some times while they tag along. They follow you properly, back and forth.