Including social issues: Maybe disability rights, family support systems, role of daughters-in-law in Indian households.
Incorporate supporting characters: Maybe a relative who is critical of Rani's inability to handle her father-in-law, or a female friend who offers advice.
Possible conflict: The father-in-law might be a traditional, strict person who has certain expectations, and his blindness could both hinder and force the family to adapt. The daughter-in-law could learn lessons about patience, empathy, and sight beyond the visual. There might be a subplot involving a relationship between the daughter-in-law and the son, or maybe the blind father-in-law's past is revealed, adding depth to his character.