In all cases under § 20-47-103 whereunder a husband is duly adjudged to be with mental illness and a guardian appointed and wherein the guardian makes a sale of the husband's interest in any of the real estate belonging to his ward, and the wife of the husband with mental illness is entitled to dower, it shall be sufficient to pass the dower interest of the wife, if she shall duly join in the petition of the guardian for the sale, and by separate instrument, duly acknowledged, convey all her interest in the lands.