410.223—Evidence of authority to execute a claim on behalf of another.
Where the claim is executed by a person other than the claimant, such person shall, at the time of filing the claim or within a reasonable time thereafter, file evidence of his authority to execute the claim on behalf of such claimant in accordance with the following rules:
(a)
If the person executing the claim is the legally appointed guardian, committee, or other legal representative of such claimant, the evidence shall be a certificate executed by the proper official of the court of appointment.
(b)
If the person executing the claim is not such a legal representative, the evidence shall be a statement describing his relationship to the claimant, the extent to which he has the care of such claimant, or his position as an officer of the institution of which the claimant is an inmate. The Administration may, at any time, require additional evidence to establish the authority of any such person.