Is it permissible for the grandmother to annul a contract for the sale of land to her deceased son before the full price has been paid, and are her grandchildren (the heirs of the deceased son) obliged to pay one-sixth of the inheritance to the other heirs despite not having received their legitimate share from the land their father purchased, and is it religiously correct that the sons of the deceased son do not inherit from their grandmother?

A sale between a father and a grandmother is valid and binding, and is not invalidated by the father's death. The heirs are obligated to pay the remaining price, after which the inheritance is distributed. If the mother's bonus and the deceased's pension are due to the deceased, they are considered part of the inheritance and are accounted for as part of the mother's share. If there is an excess in her possession, it is taken from her inheritance, unless the heirs waive their right. If there is a deficit, she is paid the remainder. If the bonus and pension are donations, their disposition is according to the granting authority. The tearing of the sales document has no legal weight, and the heirs must restore the right to its rightful owners. The Sharia courts are the ultimate authority.