Is the deceased wife's share of the inheritance calculated based on the current value of the house or its value at the time of division, in order to absolve the grandparents, especially with a dispute over the entitlement to this share?

A woman has the right to claim her mother's share of her husband's inheritance, and this right is not forfeited by the passage of time or the succession of generations. The son-in-law's financial support for her does not negate her right unless he explicitly states that it is not a donation, in which case it becomes a debt owed by him. The mother's share of the inheritance goes to her daughters, and if one of them dies, her share goes to her heirs. It is permissible, by mutual consent, to agree with the heirs to waive their share for a lesser compensation (known as takhāruj). If mutual consent is not reached, the matter must be referred to the Sharia court for a ruling.