Okla. Stat. tit. 60 § 126
In case the lands, at the time foreclosure proceedings are about to be commenced, are owned by minors, or by persons of unsound mind, such notice shall be addressed to the guardian of the minors, or persons of unsound mind, and if there is no such guardian, the Attorney General of the state or district attorney shall make application in the name of the state to the court and procure the appointment of a guardian ad litem to represent such minor, or person of unsound mind in such proceedings; thereafter the district attorney shall direct the clerk of such court to ascertain the residence or post office address of the next of kin of such minor, or person of unsound mind, and to transmit to such next of kin a copy of the petition or application to foreclose such lands, and such minor or person of unsound mind shall have ninety (90) days after the mailing of such notice to appear and defend the action.
Okla. Stat. tit. 60, § 126