Aunt Nicey believes that the caul will protect the baby and he will live.
When the narrator’s little brother is born, his parents do not name him until he is three months old. They even build a coffin.
Everybody thought he was going to die—everybody except Aunt Nicey, who had delivered him. She said he would live because he was born in a caul and cauls were made from Jesus’ nightgown.
They finally name him William Armonstrong, a name that “sounds good only on a tombstone.” He is a disappointment to everyone, but Aunt Nicey knows that he is special. The caul makes him special. It makes him different, and shows that he is under Jesus’s protect.
Sometimes babies are born with a caul, or veil. In many cultures these are considered good luck. In this case, Aunt Nicey believed Doodle would live because he was born with the caul.