Why does Hosseini reference Ernest Hemingway’s novel The Old Man and the Sea?

Laila’s father reads a paperback copy of  Ernest Hemingway’s The Old Man and the Sea. The  plot of the novella  is a metaphor for the struggle going on war ravaged Afghanistan. Hemingway’s old man, Santiago, struggles to capture an enormous fish, only to see it torn up by sharks. Every time Afghanistan gets ahead, like the Soviets leaving, they end up still in conflict.