If any member, retired member or beneficiary, is a minor, or has been adjudicated legally incapable of personally receiving and giving a valid receipt for any payment due him hereunder, the board may, unless and until claim shall have been made by a duly appointed guardian or conservator of such person, direct that such payment or any part thereof be made to such person or to such person's spouse, child, parent, brother or sister, or other person deemed by the board to be a proper person to receive such payment. Any payment so made shall be a complete discharge of any liability under the retirement system for such payment.
T.C.A. § 17-537