From the digest:
In representing a client with diminished capacity, a lawyer must sometimes make difficult judgments relating to the client’s capacity. Provided that such judgments are informed and disinterested, they should not lead to professional discipline.
When the lawyer reasonably believes that the client’s diminished capacity exposes the client to harm, the lawyer may seek the client’s informed consent to take protective measures. If the client cannot or does not give informed consent, the lawyer may be unable to protect the client against harm. A lawyer representing a competent client who may later become incapacitated may propose to the client that the client give advanced consent to protective disclosure in the event that such incapacity occurs. If appropriately limited and informed, such a consent is ethically proper.
Professional Responsibility: A Contemporary Approach 