Can you tell me the story of how Sai Baba cured a devotee's chronic asthma with his chillim?

Certainly. The story of Balaram Mankar's healing is a profound example of Sai Baba's grace. As narrated in Chapter 51, Balaram had been suffering from severe asthma for six long years. During his visit to Shirdi, Baba offered him his 'chillim' (clay pipe). Although Balaram was not a smoker and found it difficult, he took it as prasad and had one puff. The effect was immediate and miraculous. The asthma that had been a chronic ailment for years vanished in that instant and, as the text states, never returned. This powerful event shows how even a simple act by Baba could bestow complete health upon a devotee.