Each requires that the person be given an opportunity to withdraw a request and ensures that the person give express consent, so it is a premise of that provision that the person be capable and competent to give express consent. An advance directive is obviously a context in which that's not going to be true, and there may be situations, as you indicated, in which the level or type of medications used impairs decision-making capacity. Age is going to be a problem for the legislation if it intends to facilitate advance directives.
On May 3rd, 2016. See this statement in context.