I feel like my spiritual progress has stalled, especially since Baba is no longer physically present. How can I understand his nature and feel his presence again?

Chapter 43 explains that for a great Yogi like Sai Samarth, the physical form is merely an adjunct. Death is described as a characteristic of the body, not the soul, and for Baba, who is the complete Supreme Brahman, birth and death are considered false imaginations. He took an avatar with the sole desire for the welfare of his devotees. When his task was complete, he willed his body to be burned in the fire of Yoga and merged into his unmanifest form. However, he remains eternally present, having "stayed in the hearts of the devotees." By simply remembering his name, one can transcend the cycle of birth and death and feel his constant presence.