Who is Rustomji and Mehroo from Swimming Lessons and what is their importance?

In "Auspicious Occasion," Rustomji "the Curmudgeon" is a successful but hot-tempered Bombay lawyer now in his fifties, who lives with wife Mehroo, 20 years his junior, in Block A of the Firozsha Baag apartment complex. He alone refuses to contribute to communal maintenance efforts led by Nariman Hansotia, leading to a life-long enmity. Catholic-educated at St. Xavier's School, has lost his youthful idealism and believes India is merciless. He lusts after buxom housekeeper Gajra, hiding behind the newspaper lest Mehroo catch him.