Whether the inheritance certificate was issued by a court of law in the judgment made declaring him as lone successor in interest to succeed to the entire estates of his deceased father ?, if not then leaving aside his sisters, who are also the legal heirs to his deceased father and have an equal share at par with the sons as per Hindu Succession Act, 1956, without allotting any share or compensation in lieu of their share in the property is an act of deprivation of their rights in the property.Your grandfather's sisters right in their deceased father's properties is birth right. This may not be an ancestral property in the hands of your grandfather or to his sisters, instead it is self acquired property of their deceased father, because they are next generation wards of their father and not a third or fourth generation heir. Therefore your grandfather's sisters were entitled for their share in the property as a right even before the 2005 amendment act was enacted.
Whatever, if the daughters want to file a partition suit, the limitation is 12 years from the date when the right is denied (for example, if the brothers or other heirs openly refuse to give share, or they alienate the property).
I once again express that mere passage of decades without dispute does not extinguish the right, but if possession has been exclusive and adverse for more than 12 years and the daughters never asserted their right, the court may treat the claim as barred by limitation under the Limitation Act, 1963.