The theme of friendship and family is best embodied through Bruno.  Throughout the narrative, Bruno believes that the inclusiveness intrinsic to family is not merely limited to biological constraints.  Bruno seeks to emulate a spirit of inclusion to people who might not be represented in the genetic condition of family. Bruno's empathy is what makes family a universal condition that can be applied to as many people as possible.  Within this, one sees that friendship is an essential component of Bruno's universalized vision of family.  Accordingly, one sees a collapsing of both concepts into a universal sense of being where as many people as possible are acknowledged.

Bruno's universal notion of family involving friendship to all can be seen early on in the narrative.  One such way is in how Bruno treats Maria.  In hearing Maria's narrative, Bruno realizes that she is one “with a life and history all of her own.”  This spirit of friendship enables Bruno to know her more and see her as an ends in her own right and not a means to an end.  When Gretel rudely barks orders at Maria, Bruno admonishes his sister. This demonstrates how Bruno is able to expand his understanding of family through befriending another.  In acknowledging and validating the voice of "the other," Bruno is able to demonstrate a condition of being in the world that is inclusive through friendship and broadening the definition of family.

When the family moves to "Out- With," Bruno continues the same pattern of morphing friendship into family.  It is first seen with Pavel.  Bruno allows voice to emerge and complexity to identity to become evident in how Bruno understands Pavel.  He realizes that Pavel is more than simply someone who "peels vegetables and waits on tables."  This is where Bruno expands his understanding of family through respect and empathy, critical aspects of friendship.  Bruno exemplifies this tendency in his love for Shmuel.  Friendship and family merge in how Bruno approaches Shmuel.  Whether it is seeing one another as twins or brothers, honoring his commitment to cross the fence and help him, or when he walks with him, hand in hand, to the gas chamber, Bruno embodies a transcendent quality of friendship that moves it into a domain of family.  The descriptions offered in this represent how friendship and family move so close together for Bruno.  Boyne articulates this condition at different points in the narrative:  "...Despite the mayhem that followed, Bruno found that he was still holding Shmuel's hand in his own and nothing in the world would have persuaded him to let go.” In this, one sees how friendship and family are inextricable in Bruno's love for Shmuel.  When Bruno promises Shmuel that they are "best friends for life," one sees again how Bruno moves friendship and family closer to one another.  It is through the validation of another's experience and authentication of another's voice that Bruno is able to embody the theme of friendship moving into the realm of family.

The universality in which Bruno operates is deliberate. In a time period where so many were isolated from one another and narrowly defined friendship and family, Bruno exhibits a transformative behavior of what can be in the harsh face of what is.  Bruno's ability to embrace the theme of universality in which friendship and family are one in the same because of respect and validation proves to be an ideal of hope.