Payment to a person who is incapacitated to administer his property shall be valid if he has kept the thing delivered, or insofar as the payment has been beneficial to him.
Payment made to a third person shall also be valid insofar as it has redounded to the benefit of the creditor. Such benefit to the creditor need not be proved in the following cases:
(1) If after the payment, the third person acquires the creditor's rights;
(2) If the creditor ratifies the payment to the third person;
(3) If by the creditor's conduct, the debtor has been led to believe that the third person had authority to receive the payment. (1163a)