Does the gold that the mother returned to her daughter after gifting it to her become the daughter's rightful possession?

If the mother returns the gold to her son while she is in full health and sound mind, and the son immediately takes possession of it, then this is considered a valid and effective gift (hiba). The act of repaying kindness and reciprocating beneficence is a legitimate reason to specify this son for the gift, excluding his siblings. This is because justice among children in gifting is a religious obligation, and specification is not permissible except with a legitimate reason. Among these legitimate reasons are rewarding kindness and recompensing a gift, as the Messenger of Allah, peace and blessings be upon him, said: "Whoever does a favor for you, then reward him. If you do not find anything, then supplicate for him until you know that you have rewarded him."