I didn't have problems reading it but I didn't find it anything special. I find Sanderson's writing style too mechanical. While the story and character motivations are well thought out, throughout the whole book it feels like he just mechanically adds plot twists and plot devices he prepared beforehand, and the book lacks something in terms of reader's immersion in the story.

When I was reading the book, I frequently focused more on how he uses twists and devices than on the story. On the whole, the book left me with a sense of detachment. So, I can see why your brother struggles with it.