No person other than a bank or trust company shall be guardian of more than five wards at one time, unless all the wards are members of one family. Upon presentation of a petition by an attorney of the veterans administration or other interested person, alleging that a guardian is acting in a fiduciary capacity for more than five wards as herein provided and requesting his or her discharge for that reason, the court, upon proof substantiating the petition, shall require a final accounting forthwith from such guardian and shall discharge him or her from guardianships in excess of five and forthwith appoint a successor.