According to Chapter 16, what is the role of a Sadguru and how does his generosity compare to a wish-fulfilling gem?

Chapter 16 of the Sai Satcharitra explains that a Sadguru is 'Aptakama,' meaning his own desires are already fulfilled. His primary role is to help his disciples become desireless by fulfilling their desire for service. The chapter describes the Guru as the most generous giver in all three worlds, stating that he is the ultimate refuge. In a powerful comparison, the text notes that while a wish-fulfilling gem (Chintamani) can only grant what is thought of, the Guru wonderfully gives his devotee the 'Unthinkable Object,' which is Brahman itself, making his generosity supreme.