What is the significance of dreams in this novel?

The world in this novel is a dark dystopian wasteland: tit is the world talking its last dying gasps of air. The only real color appears in the man’s dreams and memories. Nightmares are merely extensions of their reality. The man can dream of a pre-apocalyptic world where as the boy cannot because he wasn't alive when the world was alive. The man dreads his "nice" dreams because he thinks it is giving up on the present.