I seriously do not understand why someone would want to euthanize a 19-year-old cat who is active and pretty healthy just for shitting next to the litter box. Mind you, this person has never taken the cat in for a check-up in its life and has no idea what medical problems might cause this behavior. Euthanasia is supposed to be a humane way to end or prevent horrible suffering, not for getting rid of a pet that's mildly inconvenient.