What are the daughter's share in father's property

I am residing in my father's property along with my mother and I am the only son. My father passed away way back in 1974 (without Will). Subsequently, the property was transferred in the name of my mother. I have two elder sisters and they have two children each. Both are married more than 30 years back and alive. The following may be clarified: 1. Kindly let me know whether my sisters have the right to claim their share as per the recent SC judgement. 2. If both the sisters are or any one passes away before the property is divided, what would be the scenario.