What caused Kaka Mahajani's skeptical friend to break his promise and bow to Sai Baba?

The transformation of Kaka Mahajani's friend is a remarkable event detailed in Chapter 35. Despite his firm resolve not to bow, the moment he set foot in the mosque, Sai Baba saw him from a distance and called out, "Why have you come in this manner?" The friend was immediately astonished because the tone of Baba's voice was a perfect imitation of his own deceased father's. The text describes a "magic power" in that speech, which made the friend feel as if he were hearing his father's familiar voice. This profound experience caused him to melt inside, completely forgetting his previous resolve, and he spontaneously bowed his head at Baba's feet.