How did Sai Baba's method of healing people change over time?

Based on the information in Chapter 0, Sai Baba's approach to healing evolved. The text mentions that initially, Maharaj actively provided medical treatments. He even told the author, whom he called 'Kaka,' "I used to give medicine to people before." He would not accept any money for this service and would even personally care for patients if they were not being looked after properly. However, at a later point, he stopped this practice of giving conventional medicine. Instead, he began to give only Udi, or sacred ash, for healing. The text notes that he had given Udi before this change as well, and people had benefited from it, but it eventually became his sole method of healing.