She's already into Book 2 so might be hard for her to stop. At that age I was also reading Stephen King and GoT like that though and I am now studying for quite a gory degree - I think some people just like that sort of stuff. :)
Here are some quotes from the book that might make you realise the content:
- "No." Lord Ramsay poured himself a cup of wine. "Laces take too long. Cut it off her." [...] Finally the gown fell away, a pale tangle round her feet. "Her small-clothes too," Ramsay commanded. Reek obeyed. [...] Ramsay rose, the firelight shining on his face. "Reek, get over here. Get her ready for me." For a moment he did not understand. "I ... do you mean ... m'lord, I have no ... I ..." "With your mouth," Lord Ramsay said. "And be quick about it. If she's not wet by the time I'm done disrobing, I will cut off that tongue of yours and nail it to the wall." Somewhere in the godswood, a raven screamed. The dagger was still in his hand. He sheathed it. Reek, my name is Reek, it rhymes with weak. Reek bent to his task.
- "No. This is some trick. It's him, it's my ... my lord, my sweet lord, he sent you, this is just some test to make sure that I love him. I do, I do, I love him more than anything." A tear ran down her cheek. "Tell him, you tell him, I'll do what he wants ... or whatever he wants ... with him ... or ... or with the dog or ... please ... he doesn't need to cut my feet off, I won't try to run away, not ever, I'll give him sons, I swear it, I swear it ..."
- This is about a character's older brother molesting him: The sound came softly, the scream of a rusted hinge. "Urri," he muttered, and woke, fearful. There is no hinge here, no door, no Urri. [...] The sound of a door opening, the scream of a rusted iron hinge. Euron has come again.
- Also someone gets their face chewed off.
- Oh and the dog hunting scenes are much more graphic and much worse than on the show.
- In the first book the sex scenes aren't so graphic but as the series goes on the scenes, especially the rape ones, are.
If she is so into fiction writing are you sure she is not accessing mature fanfiction online? This is a place where people can post their own fiction writing stemmed from Tv shows etc and it is not monitored what they can write.