Let us remember that Baba, who is a minor character in this excellent story, is characterised by his obsession with his 1947 record collection and seems to be trapped in the past. Baba is a character who is almost psychologically incapacitated through his inability to engage with the present. He spends his time listening to his records and playing games by himself, and the wedding that is occurring seems to be something that he is unable to engage with or even understand.
However, the importance of Baba's presence becomes clear when we compare him to Bim. Both characters are trapped in 1947 and have not been able to advance. In addition, through his repeated playing of his 1947 record collection, Baba causes Bim to constantly replay the events that happened during that year just as he replays his records. However, the difference between Baba and Bim is that Bim does not find this repetition of past events comforting. It only serves to exacerbate her grief and to strengthen her self-righteousness. Baba therefore is a minor character whose presence allows us to understand Bim, a central character, better. He therefore could be said to act as a foil of Bim, highlighting her dis-ease with the past by his ease with it.
The autistic Baba is described as a "plant grown underground." His presence as a character tied openly to the past functions as a reminder of how ever-present the "underground" of the past is in all the characters' lives, whether they want to acknowledge it or not. Baba especially functions to bring back memories of a pivotal year, 1947. This was a year of national unrest in India. It was also the year that Mira, the children's caretaker, finally succumbed to alcoholism and died. Meanwhile, Raja suffered from TB, and the Muslim family he had grown close to was forced to flee because of the outbreaks of violence between Muslims and Hindus. Baba's endless replaying of records from 1947 symbolizes how that disturbing year replays in the entire family's psyche.
Baba also functions as the catalyst for Bim's rage. When she blows up after he plays the same old song one more time than she can bear, he accepts her rage—and she realizes she has targeted him because he can't fight back. This burst of rage enables Bim to experience self-awareness and awareness of the value as well as the burden of family that she has bitterly born all these years. Baba's presence helps her, if inadvertently, to finally start coming to grips with the past that haunts her.