Me my father and my mother are living in a pagdi system flat with my grandmother, the rent receipt i

Me my father and my mother are living in a pagdi system flat with my grandmother, the rent receipt is in her name after my grandfather passed away around 15 years back. My question is I know as per the law if my grandmother passes away the tenancy gets transferred in the name of my father as he was residing with her when she passed away. But, she has other 4 kids apart from my father, they all stay in different parts of the city, the landlord says that if my grandmother passes away, I'll have to bring the NOC of all other children then only he will transfer in my father's name. And for a instance if we assume that the landlord transfers the tenancy in the name of my father after legal action, when in future the building goes into redevelopment, will my father get the ownership rights of the redeveloped building. Thank you