The trustee of the imprisoned debtor shall pay his debts pro rata. After paying such debts, the trustee shall apply the surplus, from time to time, to the support of the wife and children of the debtor, under the direction of the superior court. When the imprisoned debtor is lawfully discharged from his imprisonment, the trustee shall deliver to him all the estate, real and personal, of such debtor, after retaining a sufficient sum to satisfy the expenses incurred in the execution of the trust and lawful commissions therefor. The trustee shall make his returns and have his accounts audited and settled by the clerk of the superior court of the county where the proceeding was had, in like manner as provided for personal representatives. Before proceeding to the discharge of his duty, the trustee shall take and subscribe an oath, well and truly to execute his trust according to his best skill and understanding. The oath must be filed with the clerk of the superior court. (1868-9, c. 162, ss. 43, 45, 46; Code, ss. 2976, 2978, 2979; Rev., ss. 1945, 1946, 1947; C.S., s. 1628.)