How is the qirat (carat) that the father sold to his daughter before his death calculated: at the selling price, at the price of the first qirat sold after his death, or at today's price? And do her siblings share in it with her?

A father selling to his son is permissible if it is a genuine sale and the father does not favor his son in the price. However, if the sale is a trick or involves favoritism, it is impermissible and considered an injustice. If the payment of the sale is made contingent upon the father's death, this clearly involves favoritism, and the sale may not be valid unless the other heirs agree to this method. If they do not agree, the sale is not effective, and the land is returned to the inheritance.