Your grandmother is one among the legal heirs to your father's property. After her lifetime, the property left intestate would be inherited by all her legal heirs. This an inequitous provision. Hence Kerala State has made the following amendment:
Amendment of section 15.-In the Hindu Successibn Act, | 956 (Central Act 30 of 1956), in section 15, after clause (b) of sub-section (2), the following clause shall be inseried. namely:- "(c) any property inherited by a female Hindu from her pre-deceased son shall devolve, not upon the other heirs referred to in sub-section (l) in the order specified tberein, but upon the heirs of the pre-deceased son from whom she inherited the property.".
Please verify if similar amendments have been carried out in your State as well.