How did Sai Baba's Udi help the doctor's nephew from Malegaon?

According to the narrative in Chapter 34 of the Shri Sai Satcharitra, the nephew of a doctor from Malegaon was suffering from a severe bone-cyst, or Hadyavran, which no medical treatment could cure. After exhausting all remedies, his parents went to Shirdi as a last resort. They pleaded with Sai Baba, who, being the embodiment of compassion, reassured them. He gave them his sacred Udi and instructed them to smear it on the wound. Baba told them to be worry-free, implying that the application of Udi, coupled with faith in him, would heal the otherwise incurable disease and completely uproot the pain.