iam not sure about how you can get married within your family circles but in South you are allowed to get married to your Mama's son. I know we have couple of South Indians in this forum and I hope you guys agree with me. I am just looking at this Rithwick scenario from a South India's perspective.
Just Imagine guys. Rithwick grows up as MICHI's son and Sukruthi has a daughter of her own with Saket. What if Sukruthi's daughter falls in love with Rithwick and plans to marry him. GOSH that will be the biggest Kayamath (devastation) in this family. What if Saket approves the relationship but everyone is against it and don't know how to bring tell the truth. This will be the end of the relationship and I think that is how Nagpal will bring the truth out.