I didn't realize this book was designated Juvenile literature. I didn't even read it as YA. Seems adult to me, even though it's about a kid. The protagonist, Caitlin, known to her dead brother as Scout, is on the Aspie end of the spectrum. When her brother dies, Caitlin's world is rocked, and so is her dad's. Caitlin's way of processing and expressing her grief can be hard on her neurotypical father, and a lot of this book is about each of them learning to act and communicate with the other. Caitlin has to do a lot more of the work, though and is emotionally rewarded when she acts more "normal."
Erskine wrote this book because she had a kids with Aspergers, and I'm afraid the book does read as parent-of, rather than the person, a viewpoint, I think this disability in kid lit review expresses better than I can. Even so, I think it's worth a read because it gives you a look into dynamics between people with Asperger's, their families, and the world at large.
Also, it's a book about a school shooting because America is terrible.