What promise did Babasaheb Tarkhad make to his son, and how did he initially fulfill it?

To alleviate his son's concerns about leaving for Shirdi, Babasaheb Tarkhad made a solemn promise. According to Chapter 9, he assured his son, "Without offering Naivedya to Sai, no one should consume food at home... Go, I will offer Naivedya daily; be certain." Upon receiving this assurance, the son departed. True to his word, Babasaheb Tarkhad began performing the worship himself. He would pray before Sai's painted image and consistently offer a piece of sugar candy as the Naivedya, thereby initially fulfilling the vow he made to his son.