What is the ruling on a son reclaiming money he gave to his father for Hajj, which the father was unable to perform, and the son then used the money for his marriage?

The preponderant view among most scholars is that it is impermissible for a donor to retract their gift. Their evidence is the generality of the authentic hadiths from the Prophet, peace and blessings be upon him, including his saying: "The one who retracts his gift is like a dog that vomits and then returns to its vomit," and his saying: "It is not permissible for a man to give a gift and then retract it, except for a father in what he gives to his child." Based on this, a son's gift to his father has left his possession and become the property of the father. The son has no right to retract it unless the father gifts it back to him anew.