Do the lands that the father reclaimed with his own money and effort fall under the inheritance of the grandfather to be distributed among his heirs, and if so, what is the father's share for reclaiming them, and what is the share of the aunt who passed away before the grandfather's death was decided?

The concept of "Bay' al-Wafa" (sale of fidelity) is the sale of real estate or movable property with a condition that it can be reclaimed upon repayment of the price to the buyer. This sale is considered invalid by the majority of scholars, including the Maliki and Hanbali schools, and the early Hanafis and Shafi'is. This is because, in reality, it is a loan that draws benefit, which is a stratagem for usury (riba) and contradicts the essence of a sale, which is the stable transfer of ownership of the sold item.

Based on this, the sale executed by your grandfather is an invalid sale, and the land remains his property. What your father spent in reclaiming and rehabilitating the land should be compensated to him from the usufruct of the land. Any surplus should be spent on those whom your grandfather is obligated to support, and the remainder should be preserved.

If a judge rules that the grandfather is deceased, he is considered deceased from the time the ruling is issued, and his then-living heirs are entitled to the inheritance.