Yea, the ends don't justify the means, but uh...you just doomed countless innocent people to suffer terrible deaths, and even more to watch their loved ones suffer until death, and for what? The people he hurt were already dead, he was already dead. You literally made a decision that hurt billions so you could feel a little better about your connection to a terrible person. You absolutely still could have told your mother she was always right, and told Selma's parents you were sorry, but you also would have given the families of the victims some closure and saved an unknowable amount of people from terrible fates. Now everyone that died and suffered did it for nothing and you get to live with the knowledge that every single time you see someone die from cancer or any other disease your grandfather cured, it's your fault. Your parents and Selma are the only true victims of this story.