What was the specific illness that the doctor's nephew had, and why couldn't all the medical experts cure it?

According to Chapter 34, the nephew of the Malegaon doctor suffered from a disease identified as a bone-cyst, referred to as Hadyavarn in the text. This was described as a most difficult and extraordinary malady. The source highlights the failure of conventional medicine by noting that the boy's uncle was himself a degree-holding doctor, and he enlisted the help of his physician friends and even expert surgeons. Despite trying all native and foreign treatments and even attempting surgery, their efforts were exhausted, and they felt helpless. The ailment showed no improvement, demonstrating its resistance to the medical knowledge and remedies available at the time.