That’s how I was when my childhood dog passed. So many things I’d do that reminded me of her. At one point, as absurd as it was, I couldn’t play something as basic as Minecraft without having to shut it down because it reminded me of her. Just recently we lost a kitten that wasn’t going to make it, and the space heater we had keeping him warm made me cry whenever I saw it.
Your cat is very lucky to have been loved like that. I’m sure he knew that

Knowing her? I wouldn't be surprised. I actually ended up moving it straight after though lol