S.D. Codified Laws § 27A-11A-20
The chairman of the county board of mental illness may appoint someone, other than a relative of the patient, to convey the patient to the center or facility, but in no instance may a person convey persons of the opposite sex and no per diem or other compensation other than expenses may be allowed such attendant.
If any relative or member of the family of the person desires to convey such person to the center or facility, the chairman of the board may authorize such relative or member of the family to take charge of such person to convey him to the center or facility; provided, that in the judgment of the chairman of the board such relative or member of the family is a competent person for that purpose and that such person can with safety be entrusted to the care of such relative while en route.
SDCL 27A-11A-20