Complicated questions about possible cat illness

So a few years ago I had a Cornish rex named Deacon Blue. He was very lovable, and both cats we had at the time were indoors cats, we brought all strays to the vet to check for illnesses before we brought them into our house too. They only got outside once, but we found them quickly and this was YEARS before this happening, the vet told us they hadn't caught anything after we found them and brought them back inside...

His sister was at the vet for a few  days at the time. Two days before, Deacon was fat as always, loving, he ate and hung out with us... but then the next day he seemed skinny and sick, and refused to let anybody pet him or pay him any attention. The next day he crawled into Mom's bed and died... he was about 16-18 at the time.

Does anybody know anything that could have caused this?! 

Honestly, any number of things could have caused this and it is very hard for us to guess at what could have happened. At that age, though, something happening is unfortunately not wholly unexpected.  It sounds as if your cat passed on peacefully and in his own way.

If you want to talk about your loss, we encourage you to open a thread in the 'Crossing the Bridge Forum'.  It is always really hard to lose one of our faithful companions 

Mhm, I know he was pretty old and saw it coming. But I was just really surprised it happened so quickly! Thank you for your post, though!

Ah, I'll think about it ^^ Maybe I could make him a little memorial there