I am very sorry to hear this.
My all time best cat buddy, his legs stopped working. He wasn’t even really very old.
I took a box and cut 4 holes in it, so he could be upright enough to eat. Instead of eating, he gave this long, mournful cry. It was ‘let me go Home’.
That was decades ago. It’s still hard now to think of it.
Ugh, that’s the death cry. I’ve heard that too many times from my ill cats. Once you’ve heard it, you never forget it. Awful cry. :-(