I have a similarly aged child who is also studying a historical subject that is older than her age. She's a kid who practices the snowman song from Frozen at home in order to get better at not crying during it because the kids sing it at school and crying embarrasses her.
We read the historical books together. End of story. She doesn't respond to historical materials nearly as dramatically as she relates to negative events in stories, and we've had really good discussions, but there is definitely material in them that I want to be there to discuss with her.