Does the father have the right to reclaim the apartment from his children after he sold it to them for money they paid him, despite his claim that they defrauded him?

It is not permissible for the father to retract what he has gifted or sold to his children, such as an apartment, whether it was a sale or a gift of reward, because a gift of reward takes on the rulings of a sale. The authorization in the real estate registry is considered a [form of] taking possession of the sold item, because custom has established this, and taking possession is referred back to custom. It is advised to be gentle with the father, treat him kindly, and try to advise him.