Praise be to Allah.
If the grandfather gave wealth to some of his daughters because they were in need of it, either because of poverty, sickness or some other reason that dictated that they be singled out for that, there is no blame on him for that and he does not have to give to the rest of his children except in the case of need.
See the answer to question no. 36872
If a father dies and leaves behind a son and six daughters, and there is no heir apart from them, then the son gets double the share of each daughter, because Allah, may He be exalted, says (interpretation of the meaning):
to the male, a portion equal to that of two females
If the price of the land is 1000 rupees, then your father gets 250 rupees and each of his sisters gets 125 rupees.
This is how everything that was left behind by the grandfather after he died should be divided: the house in which he used to live, and in which your father is living and taking care of its maintenance, and everything else he left behind of money, property and land.
The basic principle is that the estate should be divided immediately after the death of the owner of the wealth, because delaying it may come under the heading of neglecting some people's rights or lead to rights being withheld from some.
But if your father had made an agreement with his sisters to sell the house in the future, with their willing consent, there is nothing wrong with that.
See the answer to question no. 4089 and 97842
And Allah knows best.
Reproduced from Islam QA