right of sisters on ancestral property.

First and foremost you have to clarify on what basis you say the property as Ancestral Property?

Assuming on the basis of your statement that the property in question is ancestral, your sisters are not Coparceners in the year 1995 when your father died.  Therefore they are not entitled to any share as a co-parcener.

However, on the date of death of your father (who expired without making any WILL), the property will undergo a notional partition in view of Sec. 6 of the Hindu Marriage Act, 1956.

On your father's death, the property will be divided equally between all the male members, your paternal grandmother (if alive), and your mother (if alive).

The father's share will go by way of inheritence equally between all his legal heirs (which includes his daughters i.e. your sisters).