Based on the teachings in Chapter 28, what defines a Sadguru, and why is Sai Baba considered one?

Chapter 28 provides a clear definition of a Sadguru, highlighting qualities that extend beyond mere knowledge. It states that a true Sadguru is not only a great knower of profound wisdom but also possesses the crucial ability to impart that teaching to disciples. Furthermore, a Sadguru is described as one who is firmly established in their own true nature. The chapter explains that Sai Baba perfectly embodies these qualities because He is "complete in Shabda-Brahma" (the divine word) and shows the signs of Para-Brahman (the Supreme Being). The text contrasts a Guru's role with a father's, noting that while a father gives a body subject to birth and death, a Guru's compassion is greater as it removes both birth and death.