(a) Notwithstanding the provisions of sections 19a-571 , 19a-572 , 19a-575 , 19a-575a , 19a-577 , 19a-580a and 19a-580b , comfort care and pain alleviation shall be provided in all cases.
(b) Any document executed prior to October 1, 1991, in accordance with section 19a-575 , revision of 1958, revised to January 1, 1991, and section 19a-575a shall not be invalidated by any provision of public act 91-283*. Any document executed prior to October 1, 1991, shall not be presumed to prohibit withholding or withdrawal of life support systems as defined in section 19a-570 , revision of 1958, revised to January 1, 1991, unless such prior document specifically addresses such withholding or withdrawal.