Help Puck live a happier life, please

My poor kitty Puck has had the roughest year and hes only 3.

Last year he fell out of a window serverly breaking his leg he required 3 surgery's in total to put pins in his leg then take them out again because he knocked them out of place.

While recovering from the last surgery he collected bladder stones blocking his urinary track causing him to have multiple surgery's to be unblocked as he wouldnt eat the special diet.

He is now on his special diet so I have had no further problems with his bladder or him being blocked but because of him popping the pins out of his leg it has healed wrong and his leg now needs amputation as there is nothing more the vets can do for him.

I have already put thousands towards trying to make sure my baby is okay but due to not working as much as I use to I am not able to afford the next and hopfully final surgery so I've turned to ask for help.