According to Chapter 28, what is the nature of Sai and what defines a Sadguru?

Chapter 28 teaches that Sai is not separate from anyone but dwells in all beings, pervading everything from the highest celestial being, Brahma, to the smallest ant and insect. He is described as complete in Shabda-Brahma (the divine word) and shows signs of Para-Brahman (the Supreme Being). The text defines a Sadguru as one who is proficient in both these aspects. Furthermore, a Sadguru is capable of imparting teachings to disciples and is established in their own true nature. This chapter draws a powerful distinction between a biological father, who gives a body subject to death, and the Guru, who shows greater compassion by removing the very cycle of birth and death for the devotee.