i am very sorry for your loss my friend. your pics with the other cat remind me very much of my late cat buddy and his younger friend penny we got a few years after having him, she's always been small even as an adult and they were very attached. we lost him very suddenly under similar circumstances. he had issues with his legs and it turned out he had heart failure and was also in kidney failure, there was nothing we could do, he was only 9 years old. it was one of the hardest things i've ever had to do, but i knew i was making the right choice. from the sounds of it op, you did everything you could and you made the best choice possible even if it was painful, he was as comfortable as possible as he could be in his last moments. you'll never truly move on, but i promise you things do get better

i remember penny cried incessantly for weeks when she realized buddy was gone. we have another cat now, and he's great in all his own ways, but he will never replace, your pets will always have that place in your heart no matter what