Will the grandfather be sinful for favoring males in the distribution of his property before his death, and how is this matter settled? And is the grandfather's will to one of his sons for a portion of land registered in their name considered "no will for an heir"?

Transferring property to males while excluding females violates Islamic law and is considered a bequest to an heir, which is forbidden. The sons must return what their father favored them with so that it can be divided among them, the daughters, and the wife according to the prescribed Islamic shares. For properties they exploited through rent or occupancy, they must pay the daughters' share of the rent or fair market value. If they invested capital, they guarantee its loss but are entitled to its profit. If any adult, mature heir agrees to this, their relinquishment is valid only for their own share.