Why was Kaka Mahajani's friend so shocked when he heard Sai Baba speak?

Kaka Mahajani's friend was so astonished by Sai Baba's voice because it was an exact and perfect imitation of his own deceased father's vocal style. As chapter 35 describes, the moment the friend set foot in the mosque, Baba called out to him. The specific words and the charming tone Baba used were so familiar that the friend was amazed in his mind, recognizing it as his father's way of speaking. This magical power in Baba's speech, which felt like a perfect imitation, caused the friend to melt inside and abandon his preconceived notions about the saint.