I guess she just found out a skeleton in her closet, everyone has some, and most are dark, and deserve to stay hidden. She did seem quite distressed at the news.
I am sure she loved her grandpa very much. Of course she had no control over his actions but will always feel a responsibility to claim her grandfathers legacy and hopefully make amends for it in the future.
You cant change the past but you can take steps to right a wrong in the future.
I would encourage her to visit the Anne Frank Museum, and some of the concentration camp museums and the gravesides of Holocaust victims to attone for his actions.
Boston has a beautiful memorial for the victims. and other places do also.
Knowledge will stop hate in its tracks. I would love to say we have evolved so much the unnecessary deaths due to hate will stop and be no more.
I look at the headlines and they are scary. I just have to hope that the lessons I taught my children to love not hate stay strong; and they go on to the next generation and more.