Can the inheritance of a deceased father be claimed from his grandmother after she relinquished it in the presence of his paternal uncles and aunts?

The mother of the deceased receives one-sixth due to the presence of a lineal descendant, and his wife receives one-eighth due to the presence of a lineal descendant. The remaining inheritance is for the four sons, by way of ta'sib (residuary heirship), to be divided equally among them. The inheritance is divided into ninety-six shares: the mother receives sixteen shares, the wife receives twelve shares, and each son receives seventeen shares.

As for the grandmother's waiver of her share, if it occurred during her death illness, it is a bequest (wasiyyah) that is executed within the limits of one-third unless the heirs consent. If it occurred during her good health, it is a gift (hibah), and the heirs have no right to claim anything from it. These disputed matters should be referred to the Sharia court or to someone qualified to adjudicate, to hear all parties involved.