Who is Nalini from Sister of My Heart and what is their importance?

Nalini is Sudha's mother. She eloped with Gopal when he proposed to her after he saw her washing clothes in a creek. Despite her poor background, Nalini often talks about how much better things were when she lived with her father. Sudha believes this means her mother's family was rich. It is Pishi, however, who tells her from where her mother really came. Nalini often frowns, her daughter is unsure if this frown is as a result of worry or displeasure.