Section 7. No final account or discharge of a guardian of a mentally retarded person shall be allowed unless at least seven days’ notice has been given to the department of mental retardation in the case of a mentally retarded person. No account of a guardian of a mentally ill or mentally retarded person or of a conservator shall be allowed without such notice as the court may order to the United States veterans’ bureau or its successor if the ward is entitled to any benefit, estate or income paid or payable by or through said bureau or its successor.