Is it permissible in Sharia for a father to annul the sale of a house he had agreed to sell, in order to end ongoing family disputes related to this house, provided that he returns the down payment received to the buyer?

If the sale fulfills its conditions and pillars, it becomes valid and binding on both parties, and cannot be revoked except by annulment (Iqalah). The matter regarding annulment rests with the buyer; if he wishes, he agrees, and if he wishes, he refuses. He cannot be compelled to it, but it can be requested from him. He can also be enticed by offering him an additional amount beyond what he paid, based on the opinion of those who consider annulment a sale. Reconciliation among relatives is more preferable and better than immediate material gains.