What is Bruno's perspective on war/death and how does he react in The Boy in the Striped Pajamas by John Boyne?

Bruno's perspective on war and death is complete innocence.  In short, Bruno has no perspective.  In fact, if Bruno had one, he would disagree with both war and killing.  (Death, of course, is eventually inevitable.)  Look at the following quotation:

What exactly was the difference? He wondered to himself. And who decided which people wore the striped pajamas and which people wore the uniforms?

Here Bruno is pondering the difference between himself (a young German), the Nazi soldiers, and the Jewish people trapped in Auschwitz.  In his innocence, Bruno attains wisdom:  there are no real differences.  They are all people who are worthy of respect and friendship.  Bruno also has further revelations about himself and Shmuel.  Bruno says, "We're not supposed to be friends, you and me. We're meant to be enemies. Did you know that?"  Bruno is absolutely disgusted with this revelation.  Shmuel is Bruno's very best friend.  This friendship is proved in the deepest of ways.  Bruno escapes "into" Auschwitz in order to help Shmuel find his father.  Eventually, Shmuel and Bruno hold hands as they walk into the gas chamber together to their deaths.  In other words, everything about killing others (including while at war) is deplorable to Bruno.  Bruno is more interested in friendship and trust.