Is the sister entitled to demand her share in the house at the current price after she refused to take her share at the old price when her siblings sold their shares, and is giving her the new price considered differentiation between her and her sister who took her share at the old price?

The division of inheritance is a religious obligation. If a brother purchases the rights of his siblings in a house with their consent, the contract is valid if they are adult and of sound mind. However, if there is a minor or someone of diminished capacity among them, the contract is not enforceable unless approved by their guardian, and provided that it serves their best interest. The sister who has not relinquished her right is entitled to retain her share or sell it at a price she deems acceptable. If she sells it for more than what her brothers sold their shares for, there is no injustice to them as long as they sold with their consent. Matters of inheritance are serious and complex, and a mere fatwa (definition) is insufficient; rather, they must be brought before Sharia (definition) courts for investigation.