(2) Special rule.--If, under State law, a child with a disability who has reached the age of majority under State law, who has not been determined to be incompetent, but who is determined not to have the ability to provide informed consent with respect to the educational program of the child, the State shall establish procedures for appointing the parent of the child, or if the parent is not available, another appropriate individual, to represent the educational interests of the child throughout the period of eligibility of the child under this part.