I don't think Rakesh was a hypocrite towards his father.

One of Desai's most compelling points in "A Devoted Son" is the downside of social expectation.  In this case, it is in how parental expectations can contain unforeseen circumstances.  Rakesh's parents don't really ask him what he wants out of his life.  Rather, the social conventions of him doing well in school, getting into a good university, marrying a bride of his parents' choice, and holding a successful position as a doctor are all expected of him.  He dutifully follows what his parents lay out for him, meeting these external standards of success and happiness.

When he tends to his father, it is almost as these expectations are realized. Rakesh's approach to his father is reflective of a socially designed notion of love and respect.  Just as his father never really asked him what the boy wanted out of life, Rakesh does not open up an indepth dialogue on how to take care of the father.  Rakesh simply does what is "expected" of him as a doctor and a son.  He limits his father's food intake.  He prescribes a cocktail of medicines.  Rakesh's internalization of social expectation makes him do his job of being a son "who actually refused his father the food he craved."

I don't think that Rakesh is hypocritical.  To be hypocritical is to be knowingly inauthentic, to deliberately pretend.  I don't see Rakesh as doing that. Rather, I see him representing a world where people live for social expectation and nothing else.