Can I still be a legal heir if Tenancy rights waived

I along with my sister and father were living in a room part of old chawl in central Mumbai which has been taken over recently by municipal corporation. There is a redevelopment proposal floated and now the developer is paying the rent to municipal corporation on everyone's behalf. I am currently out of India for employment purpose since last 2 years and will come back next year. The room was on my mother's name and she expired 3 weeks back. Now my sister asking to transfer the tenancy rights to her name as she cannot do any transactions with Municipal corporation or developer (as I am abroad) as they are asking for all legal heirs to be present. Instead of surrendering my tenancy rights, I gave her POA however she is asking to transfer tenancy rights to her name as she says it is only way Municipal corporation/developer telling her she can operate alone on everyone's behalf and a lawyer told her that my father and me would still be legal heir and have all rights on redeveloped property and will be part of redeveloped property even after tenanacy rights transfer. I am still not convinced and think it is fishy. Shouldn't POA alone not suffice and do I really need to surrender tenancy rights?