How does the author portray the true destruction without a drop of blood

The lingering question occurs to the reader as the story closes and the narrator bemoans the old man’s impending death. Why doesn’t the narrator help the old man at least part of the way to the trucks bound for Barcelona? Surely everyone, including the narrator and the old man, is going in the same direction. Surely it would not be a great imposition for the narrator to help a 76-year-old man who had already walked 12 kilometers along at least part of the way to safety. Are the old man’s fatalism and the narrator’s despair justified? Since this story began as a news dispatch recounting an encounter Hemingway actually had, this question takes on more than academic significance.