What is the dream that Billy has about Boyd?

The following day passes slowly. Billy finds the knife that had been used to stab the horse. Billy finds red ants near Boyd's body and picks up the body, wedging it into the fork of a tree. The packhorse is gone and he doesn't see it again though he searches. That night he dreams about Boyd. In the dream, Boyd squats down beside the fire and Billy asks what it's like to be dead but Boyd only looks away without answering. When Billy wakes and sees Billy's body in the tree, he cries.