Oh I can relate and have a rescued kitty just like that who is now sitting on my lap after four years of loving !!!
I think the joint pain does get easier and hope it does for you too, I also lost my old cat to spinal cancer during my chemo which upset me more than my own dx, Max is gorgous but its nice to have these furrys to help us!!!
My friend has tow rescue flame point siamese and there's a group on FB I think, she's a 25 year survivor who had 22 nodes pos so a real inspiration for me!