How did Sai Baba's Udi help the doctor's nephew from Malegaon who was suffering from a bone-cyst?

According to Chapter 34 of the Shri Sai Satcharitra, a doctor's nephew from Malegaon was afflicted with a terrible bone-cyst, or Hadyavran, which proved incurable by any available medical treatments. His uncle, a degree-holding doctor, and other expert surgeons had exhausted all native and foreign remedies, including surgery, to no avail. The boy was in immense pain. As a last resort, the family heard of Sai Baba and traveled to Shirdi. After they pleaded with him, Baba, the embodiment of compassion, gave them Udi and instructed them to apply it to the wound. The chapter states that smearing the Udi from Sai’s hand completely uprooted the pain and cured the seemingly incurable disease, demonstrating the sacred ash's profound healing power.