Section 17. Upon the filing of such petition the court shall appoint a time and place for a hearing, and shall cause not less than seven days’ notice thereof to be given to the person for whom a conservator is to be appointed, except that the court may for cause shown direct that a shorter notice be given. No appointment shall be made without such notice to the heirs apparent or presumptive of such person, including the husband or wife, if any, and, if such person is entitled to any benefit, estate or income paid or payable by or through the United States veterans’ bureau or its successor, to said bureau or its successor, as the court may order. If the person for whose property the conservator is to be appointed is himself the petitioner or assents in writing to the petition, no notice shall be required, except to said bureau or its successor if such person is so entitled.