(a) The attorney general shall defend any person described by Section 41.312(a) in an action if:
(1) the unit requests the attorney general defend the person; and
(2) the action arises from a service performed under this chapter or Chapter 841, Health and Safety Code.
(b) The unit or the person described by Section 41.312(a) is not responsible for and may not pay any costs associated with the assistance.