Who was the author's close friend whose personal tragedy almost prevented the author's trip to Shirdi?

Chapter 2 recounts a story about a very close friend of the author whose tragic experience caused the author to reconsider his trip to Shirdi. This friend was the son of a Guru and had received grace. While in Lonavala, his only son, who was healthy and virtuous, was suddenly stricken with fever and died. This happened despite trying all human remedies, performing divine rituals, and even having the Guru sit by the son's side. Witnessing this terrible crisis and the failure of even a Guru's presence to prevent it deeply affected the author.