The original question had to be edited down. I tend to think that the dynamic of the relationship between Rakesh and his father is best shown in the story's ending. It is at this point where one of the most essential themes to the work is illuminated. Consider Rakesh's father's revelation about his son and the treatment he receives at the hands of a "devoted" child:
My own son. If I ask him for one more piece of bread, he says no, papa, I weighed out the atta myself and I can’t allow you to have more than two hundred grams of cereal a day. He weighs the food he gives me, Bhatia—he has scales to weigh it on. That is what it has come to.
This quote shows the level of "devotion" that is evident in the relationship between father and son. Desai leaves it ambiguous enough so that the reader can see multiple experiences of "devotion" in both literal and ironic senses in this quote. The "devotion" that Rakesh has in keeping his father alive has come at the cost of removing elements that the father deems essential to living. For Rakesh's father, devotion has rendered life as being one without life. At the same time, this devotion can reveal a condition that ends up trapping more than liberating. Rakesh's devotion, something that had been encouraged by his parents, is something that knows no ends. Even if the cost is isolating emotion from the relationship, the goal of devotion is something in which Rakesh's father realizes that is more imprisoning than anything else. Devotion is brought into question with the quote, and with it, an illumination of a dominant theme in the short story.