Intersectional issues
Intersectionality is just a sociological way of saying that problems can stack on top of one another. When someone's identity happens to be at an "intersection," typically that makes them more likely to suffer from chronic mental health issues and a whole litany of other issues. Consider Binh and Tuyen, two siblings separated from their third sibling by warfare, without knowing what became of him. That is one issue, but also, Tuyen is gay, and she lives in a low-income environment as an immigrant. She is at the "intersection" of many challenging roles.
Disenfranchisement and systemic injustice
These characters are not just floating people—they represent their struggles and their point of view. We see people from many different disenfranchised people groups in this book, and the main idea of the novel is how they sort through their difficulties. Each character has tendencies and vices that affect their ability to solve problems, but they share the problems. As a gay immigrant whose family has a painful history of political oppression, Tuyen handles things her way, and her brother handles the same problems in his own way—typically in an opposite way.
Violence versus community
In the end of the novel, Jamal assaults Quy and leaves him for dead, stealing their family BMW. Ironically, Quy was a long lost relative who was simply hiding by the car to surprise his family. Instead of a long-awaited reunion, they find their own flesh and blood, beaten by a family friend. The confusion can be clarified in one simply idea: Jamal has damaged his own community by being a violent person. Instead of helping himself, he hurts others, and the punishment for that is that his own neighborhood is dangerous.
