In the story of the grapes, what was the purpose of the other devotee, Babasaheb Tarkhad?

In the narrative from Chapter 35, Babasaheb Tarkhad plays a crucial role as a witness and a point of comparison that highlights the personal nature of Baba's miracle for Boss Dharamsee. Initially, Tarkhad sets the stage by telling the curious Dharamsee that people come simply 'For Darshan.' More importantly, after Dharamsee experiences the miracle of the seedless grapes, he asks Tarkhad about his own portion. Tarkhad confirms that his grapes still had seeds. This confirmation was key, as it made Dharamsee 'extremely surprised' and proved to him that the miracle was not a general occurrence but was specifically intended for him, addressing his individual state of mind and doubt.