It's significant that the protagonist is known solely by his connection to Doodle as "Brother." This detail emphasizes that brotherhood is a central theme. Brother's affection for Doodle is mixed with cruelty and shame. Doodle is deeply attached to Brother, heavily depending on him, and his biggest fear is being left alone. He is terrified when Brother threatens to abandon him in the barn loft if he doesn't touch the coffin, pleading, "'Don't leave me.'" He repeats these words with increasing desperation on the day he dies. Frustrated by Doodle's failure to meet his physical expectations, Brother runs ahead in the rain, prompting Doodle to cry out, "Brother, Brother, don't leave me! Don't leave me!" Brother does leave him momentarily, which leads to Doodle's death.

Set against the backdrop of World War I, Doodle's pleas and the theme of brotherhood resonate on a larger scale. In war literature and memorials, brotherhood among soldiers enduring horrific conditions in muddy trenches was a common theme. Loyalty among soldiers was vital; if a soldier was injured, his survival often depended on the loyalty or betrayal of his comrades. There are countless stories of heroism where men risked their lives to save a wounded comrade, as well as tragic accounts of the injured being abandoned. More broadly, the devastation of the war highlighted the importance of embracing the ideal of brotherhood among all people, transcending differences in nationality, race, or religion.