What qualities made the author, Hemadpant, the perfect, ego-less devotee to write Sai Baba's life story from the very beginning?

The source material from Chapter 2 presents a different picture, suggesting the author was not initially a perfect, ego-less devotee. In fact, the text describes the writer who became Hemadpant as being "mischievous, talkative, cynical, and critical" in his early days. He was "always proud of his own wisdom" and "prone to argumentation." The process of writing the book was itself a transformative journey for him. Sai Baba's condition for providing full assistance was that the author "should dissolve his ego and surrender it at my feet." It was through this process of surrender that he became a suitable instrument for Sai Baba, who declared, "I myself shall enter with 'I-ness' and write with my own hand."