Must the youngest son return to the middle son the amount the latter paid for the purchase of the old house, based on the youngest son's promise to return half of the new house to him after his forced relinquishment of it?

If a father buys land for his son, it is considered a gift (hiba), and justice must be observed among the children regarding it. If the father builds the house for himself, the house belongs to him, and the son has the right to claim what he spent if he was not a volunteer. If he builds for his son, the ruling is the same as for a gift. Compelling the son to relinquish half of the house is permissible if the house is owned by the father, or if the relinquishment achieves equality among the children while preserving the son's right to what he spent. However, if the gift was valid, compulsion is not permissible, and the younger son must return half. The father's will not to return it is not binding. We advise resolving the dispute through reconciliation or by referring it to the court.