What is the main conflict in Outer Dark by Cormac McCarthy?

Rinthy Holme has a baby boy. She and her brother, Culla, live in a rustic cabin in the woods in Appalachia. When Rinthy goes into labor, she pleads with Culla to go get a midwife to help her. He refuses because the midwife might tell others about the baby. Culla reluctantly helps Rinthy when she gives birth. He takes the healthy baby boy to the woods and leaves it for dead. Rinthy asks for the baby but is told by Culla that the baby was sickly and died. A tinker (vendor) who had stopped by the Holme cabin earlier finds the baby and brings it to a nurse in a nearby town.