Based on Chapter 28, what are the defining qualities of a Sadguru, and how is a Guru's compassion superior to that of a parent?

Chapter 28 provides a profound definition of a Sadguru, stating that such a being is proficient in both Shabda-Brahma (the divine word) and Para-Brahman (the Supreme Being), and is able to impart teachings to disciples. Sai Baba is presented as having these qualities. The chapter further elevates the Guru's role by contrasting it with a father's. It states that while a father gives birth to the physical body, which is inevitably subject to death, the Guru possesses an "additional compassion" because a true Guru's grace removes the devotee from the entire cycle of birth and death.