What is the ruling concerning money that a father instructed to be handed over to two individuals, but then he died before handing it over to them, knowing that one of the sums was given to a third party for delivery, while the other remained with him awaiting the return of its owner who was traveling?

If you were agents for your father in delivering those funds, then the agency becomes void upon the death of the principal or the agent. If the funds were a gift, and your father died before the recipient took possession of it, then it is to be returned to your father's heirs. However, if they were debts, then the heirs are obligated to pay them back to their owners from the estate.