For the purposes of this subchapter, the term “aid to the permanently and totally disabled” means money payments to needy individuals eighteen years of age or older who are permanently and totally disabled, but does not include any such payments to or care in behalf of any individual who is an inmate of a public institution (except as a patient in a medical institution) or any individual who is a patient in an institution for tuberculosis or mental diseases. Such term also includes payments which are not included within the meaning of such term under the preceding sentence, but which would be so included except that they are made on behalf of such a needy individual to another individual who (as determined in accordance with standards prescribed by the Secretary) is interested in or concerned with the welfare of such needy individual, but only with respect to a State whose State plan approved under section
1352 of this title includes provision for—
At the option of a State (if its plan approved under this subchapter so provides), such term