My neighbour had an old Cat and it came in dragging it's back legs. She took her cat to the vet and was told that it was not in pain so he didn't think it should be put down.
It's condition worsened until after several more expensive vet visits I told her she needed think about insisting on euthenising the poor creature and that it seemed to me the vet was milking the situation.
She took it back to the vet when it was dragging it's lower body sideways and it's front paws were being injured and finally got the vet to end it.
I love animals, particularly cats and it hurt me to see this poor thing dragging itself around. She took her loss very badly and I'm not sure I was wrong to encourage the ending of it's life.