This is an interesting question. Certainly, I think that there would have been some level of awkwardness between Ratan and the postmaster's mother. However, I think that this could have been overcome. Ratan had taken to appropriating his mother as her own. In their conversations, when the postmaster would refer to his mother and sister, Tagore indicates that Ratan would appropriate them, as well, by using terms of familiarity. Being an orphan, Ratan would not possess any other frame of reference other than to accept the postmaster's mother as her own. Even if the postmaster's mother would not have been a good sort, it is not as if Ratan, being an orphan, would have her own mother to which she could cling or run. This would have made the transition to the postmaster's mother's life easier for her and made Ratan more adroit for adaptation. If the postmaster had declared his loyalty and sense of respect for Ratan, it would have been something that Ratan's mother would have accepted over time. To bring Ratan home to his mother would have displayed a sense of commitment and honor to Ratan that the postmaster lacked at the end of the story.