Why was Amir Shakkar initially so unhappy about staying in the Chavadi, and what made him change his mind and stay there happily?

Amir Shakkar was initially very miserable and his mind was in turmoil because the conditions of the Chavadi were completely contrary to his health needs. Chapter 22 explains that he suffered from rheumatism, yet the place was extremely damp, cold, and uncomfortable. However, he was convinced to stay after Baba gave him firm instructions. Baba's words were considered the only true medicine. Amir accepted that the company of Sai was the "Great Prasad" and, holding onto this faith, he accepted Baba's word as medicine and stayed happily in the Chavadi for nine months.