Same here, this episode really hurt because I've experienced this dynamic in my own family. both with my parents when I was a kid and then with my daughter and husband (though without a heart attack or death, thank goodness). (TMI warning: Feel free to skip the next part, but I promise that I will relate it to the show.) When I was a kid, my mother was the critical one who made me feel like I wasn't good enough, and my father was loving and the peacekeeper. When I was in my 20s, my parents got divorced (my mother's choice) and I became estranged from her, though she periodically sent me cruel letters about what a terrible daughter I was. So when I got married, I did not want to have children because I thought I would be a bad mother. I was finally convinced by my husband and with the help of therapy that I was not doomed to repeat the past, and when I had a daughter I became Supermom...for a while. But she was a very independent and fierce personality (like Devi), and as she got older (especially teens) we often argued over what she was allowed to do and were very angry with each other. My husband was the "nice" and "easy" parent and tried to act as peacekeeper, but that just made it worse because I felt like he was treating me like a child. I often was depressed at being such a bad mother and felt like giving up because I feared she would stop loving me and we would become estranged like my mother and I. So I empathized with Nalini's outburst about Devi not being her child, and I understood that she said that not because she hated Devi or no longer wanted her, but because she felt hopeless about their relationship.
Fast forward to my daughter in her 20s and 30s: Our relationship has improved a lot, in part because we have been able to have long, honest discussions about our feelings. She knows I love her unconditionally, and she has reassured me that she loves me and will never cut me out of her life. She had a daughter 3-1/2 years ago, and I am happy to see that my mothering mistakes are not being repeated--my daughter is loving and incredibly patient with her daughter, but she does sometimes share with me her fear of losing patience and harming the relationship. All of this is to say that, even though they are fictional characters, I am hoping that Nalini and Devi can repair their relationship by talking honestly and sharing their grief.