Actually Kevorkian would never kill a defenseless person, with no evidence what that person wanted. He didn't kill them. He merely provided the means, for those who really DID want to end their life, to make it easier. And he is in jail.
What Greer did is MURDER: ordered the murder of a defenseless woman, whose wishes were NOT established beyond a reasonable doubt, a person, who was not suffering, was not in pain, had a loving family, who wanted to take care of her. Kevorkian is a saint, in comparison.
Perhaps, the Dr. Singer would be a better example?