Caveat emptor. It was up to your sister to NOT be gullible. If she didn't want to have a sexual relationship, why DID she have sex?
Her desperation, her incompleteness as a person, made her ignore the realities and believe her fantasies instead. Now, don't think I approve of what he did. But it was your sister herself who made a victim out of herself.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.