He knew a lot about his grandparents - and perhaps he feels he's been endowed with abilities to go into people's heads who are long dead - but, to a certain extent, he's making it up.
The book has many different characteristics: some are extremely old-fashioned storytelling traits, but there are also a fair number of postmodern traits, and the self-consciousness is one.
When I wrote The Virgin Suicides, I gave myself very strict rules about the narrative voice: the boys would only be able to report what they had seen or found or what had been told to them.
It wasn't conscious, but I guess that one book is the reaction to the other. The first is so imprisoned in a male point-of-view, and the second is a point-of-view that can go anywhere it wants.
At the same time, it's a family story and more of an epic. I needed the third-person. I tried to give a sense that Cal, in writing his story, is perhaps inventing his past as much as recalling it.