I've read Diana Gabaldon, and imagine them to be similar, am I right?
No, you are very not right ...
Take the Red Wedding ... the show actually cencored it as in the book once they have killed Robb Stark they find his Dire Wolf, Grey Wind, and decapitate both, before sewing the dire wolf's head to Robb's body, putting a crown on it's head, to parade it through the streets in a mockery of the King of the North ...
Even GRRM said that he was really badly affected by the Red Wedding: ...the Red Wedding was the hardest thing I ever wrote. I wrote the entire book, I skipped over the Red Wedding and wrote all the way to the end, and then I came back and did the Red Wedding, because it was just emotionally difficult to do that. But you know, hopefully, if it's hard to write, it'll be hard to read, too. It’ll affect the reader emotionally. I mean if the reader is just reading the book and terrible things happen, and they just put it aside and say, “What’s for dinner,” you’ve kind of failed. Your characters haven't achieved any reality here.
If even the writer, who thought up then wrote down the entire series, emotionally struggled to deal with parts of the book, how do you expect a teenager to deal with it adequately, especially if their parents haven't read the book or understand it's complexities?