She is over 20 and has renal failure. The vet told me over a year ago that she wouldn't last much longer, she would intoxicate her self and go into a coma. ("How will we know?" asked DH. She is not an active cat...) She is incontinent and in the last few days her back legs just sort of splay out behind her and she can't walk properly. Despite this, she insists on going outside - is outside now and won't come in, even though it's really cold. Do you think the time has come to get the vet to put herto sleep?