Did Sai Baba ever interact with his devotees in their dreams? If so, how?

Yes, Sai Baba would powerfully intervene in his devotees' lives even in their dreams. Chapter 19 provides specific examples of this unique form of instruction. For instance, it is mentioned that for devotees who had a strong addiction to alcohol, Baba would appear to them in their dreams, sit on their chest, and physically press their hands and feet until they promised to never touch liquor again. In another instance from the same chapter, he is described as writing the 'Guru-Brahma' mantra in a devotee's dream, demonstrating the "unprecedented novelty of his instruction" through both direct words and dream visitations.