Telling this story from the perspective of a 9-year-old boy really gives Foer a lot of freedom to explore the types of "off-the-wall" thoughts a lot of us (I think) have when trying to make sense of tragedy. As grown-ups, I think we censor our thoughts or tend to try to reason our way out of grief. Oskar doesn't try to reason his way out of his grief. He just tries to arrange his world so it makes some sort of sense after something far beyond understanding happens. It's not surprising that this way of organizing his world looks strange to those not inside his grief. 
 Layered in with Oskar's story is the story of his grandparents and their response to the fire-bombing of Dresden when they were teenagers. There's a comment here about the long-term ramifications of not finding a way to deal with one's grief or perhaps simply about the length of time it can take to find a way to live with grief and with a reality that is incongruous with what we think we know about the world. 
 I stayed up late and finished this book in one day (and night), something I haven't done since I became a mother because in most circumstances, sleep has been more important than finishing a story. I'm going to try to read books that are less engaging for the next couple of months so I can catch up on my shut-eye.