So sorry to hear this. I never understood “cat people” until my wife picked up three of our own. Lovely little creatures.
I’m sorry to hear that Clarence didn’t make it. He sounds like he was very special; may he rest in peace.
Sorry for your loss. 
It sounded like he had a good run, though, and lived his final years in a house full of love. That’s what matters most.
Hugs. And what ArchiveGuy said.
I’m crying for Clarence…
Last week I had to put my bitch-kitty to sleep (bone cancer), and a month before that, Moonpie got killed by a gator.
It sucks losing cats.
platonic man-hugs to you.