What are the conditions for a father to revoke a gift given to his son?

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There are four conditions for a father to revoke a gift made to his son. The first condition is that the gifted item must remain in the ownership of the son. If the item leaves the son's possession through sale, gift, endowment (waqf), inheritance, or any other means, the father cannot revoke the gift because this invalidates the ownership of a third party. If the item returns to the son through a new legal cause, such as a sale, gift, bequest, or inheritance, the father cannot revoke the gift, as this represents a new title not derived from the original gift from the father, making revocation impossible, similar to property never gifted to him. However, if the ownership returns due to the dissolution of a prior sale (such as revocation due to a defect, mutual rescission, or the buyer's bankruptcy), there are two views. One view permits revocation because the impediment is removed and ownership returned via the original cause, resembling revocation due to the option of the council or condition. The second view prohibits revocation because ownership returned after being established in another party, similar to returning via a new gift. If the return is due to the dissolution of a sale based on the option of the condition or the council, the father may revoke because the ownership never fully settled.