Can you tell me about Narayanrao's experience with illness after Sai Baba's Samadhi?

Certainly. According to Chapter 33, a year after Sai Baba's Samadhi, a devotee named Narayanrao was afflicted by a severe illness. His condition was so dire that all medicines and worldly treatments had failed. Despite being tormented by his sickness, Narayanrao maintained constant meditation on Baba day and night. One night, he had a dream in which Sai Baba appeared from an underground chamber and gave him assurance, stating that he would start to see improvement the very next day and would be able to sit up within a week. Just as Baba promised, Narayanrao recovered and later narrated this experience when he came to Shirdi for the darshan of the Samadhi.