I read there was some tension between Tarkhad and his son about the pooja. What was the religious difference between them?

The source of tension stemmed from their different religious affiliations and practices, as mentioned in Chapter 9. The son was a devout devotee of Sai Baba who strictly followed the ritual of daily idol worship, including making food offerings (Naivedya). In contrast, his father, Babasaheb Tarkhad, was a follower of the Prarthana Samaj. This affiliation made the son doubt whether his father would be willing or able to properly perform the "effort of idol worship" according to his standards. This difference in belief created what the text calls a "great puzzle for the son," causing him to hesitate before entrusting this sacred daily duty to his father.