Did you notice that all the characters in the book are orphans? All of them. R doesn't ever mention parents, you know, being a zombie and all. Perry's mother is dead, then his father dies. Nora's parents are dead. Julie's mother is dead, then her father dies. Pretty much the second her father dies, R remarks, "Julie has become an orphan. […] Her grief will catch up to her eventually and demand its due" (2.8.225).
That's sad. But if we're being honest, we have to say that there is no grief about lost parents anywhere in the book. So what's with all the orphans? Isaac Marion even dedicates this book, "For the foster kids I've met." Is this just a shout-out to all the orphans out there, or is there a greater point to the recurring symbol?