What is the Islamic legal ruling concerning a sum of money paid by a husband to his wife, and then to her brother, with the intention of the wife participating with her brothers in a company, and the ruling on the recovery of this sum upon divorce, taking into consideration the three presented scenarios?

Whoever grants a gift and hands it over to the donee or their agent is not permitted to revoke it, for the Prophet, peace and blessings be upon him, said: "The one who revokes his gift is like a dog that vomits and then returns to its vomit."

If the initial amount paid (10,800) was a gift from the husband to the brother and it was received, then it is a binding gift. The same applies to the nine thousand if the husband paid it as a gift to the brother and he received it.

However, if he paid it considering it his own, then the brother has no right to it, nor to the remaining promised amount (15,0) due to its not being received before the husband's revocation. The lack of written documentation for the gift does not matter, as mere possession is sufficient.