"involuntary" euthanasia is a bit of a misnomer I think. I understood it meant Euthanasia where the soon-to-be-deceased was no longer capapble of issuing relevant instructions, BUT had left clear instructions about their future medical care in the form of, for example, an Advance Health Directive which operates usually in association with an Enduring Power of Attorney. So it's not really "involuntary" because it's something that the person has left clear instructions about but is no longer capable of carrying through themselves.