According to the medicine man, why did Ekwefi's children keep dying? What does he do to prevent another death of Ekwefi's baby? Why?

The medicine man has said that she has given birth to an ogbanje, a wicked child who, after dying, returns to its mother's womb to be reborn and die again. The medicine man advises mutilating the dead bodies of the infants in hopes of scaring them away from reentering their mother’s womb.