Can you explain what happened with the Dakshina between Sai Baba, Kaka, and his friend?

The incident with the Dakshina is a notable part of the story in Chapter 35. After Kaka Mahajani's friend had already been moved by Baba's voice and bowed, Baba asked for Dakshina, but pointedly only from Kaka. Later, when it was time for them to return to Mumbai, Kaka again requested permission to leave. At this point, Baba asked him for a specific amount, saying, "Give me seventeen rupees." Throughout these interactions, Baba asked for nothing from the friend who had initially vowed not to give any Dakshina. This act of being ignored by Baba made the friend feel restless in his mind.