(a) Regardless of the receipt of written notice of the appointment of a guardian or other person legally vested with the care of the person or estate of an incompetent or a minor who is receiving or claiming benefits or to whom any right or privilege is extended under the law, the Board may, in its discretion, validly recognize actions by and conduct transactions with others acting on behalf of the individual found by the Board to be a minor or to be unable to manage his or her affairs, if the Board finds such actions or transactions to be in the best interest of such individual.

(b) In the absence of a written notice of the appointment of a guardian or other person legally vested with the care of the person or estate of an incompetent or minor, the Board shall, except where special circumstances appear, recognize a person to act on behalf of an individual under the following circumstances:

(1) When the individual has been adjudged mentally incompetent by a court having jurisdiction to do so;

(2) When the individual has been committed to a mental institution by a court having jurisdiction to do so;

(3) When the individual is an inmate of a mental institution;

(4) When the individual is less than 16 years of age; or

(5) When the individual is between 16 and 18 years of age and is in the care of another person and does not have the capacity to act on his or her own behalf.