Property Related Dispute - Hindu Succession (Amendment) Act, 2005

Ancestral land (1.2 acres) of my grandfather (died on 1950’s), he had one son (my father) and two daughters (both daughters date of birth is in 1940’s and Date of marriage is 1960’s; out of which one daughter is dead 5/5/2012). My father died on April 2019 now one sister of my father and other sisters who passed in 2012(daughter and sons) are asking for the share in land. Firstly, do they get share in the property? Secondly, I believe ‘’the court held that the amended provisions of the Hindu Succession (Amendment) Act, 2005, could not have retrospective effect despite it being a social legislation. The court said the father would have had to be alive on September 9, 2005, if the daughter were to become a co-sharer with her male siblings.’’ If this above is correct, could anyone please share judgement or other information which can be useful in above case?