Md. Code, Estates and Trusts § 13–712

(a) The court may approve a request for the withholding or withdrawal of a life-sustaining procedure from a disabled person on the basis of a substituted judgment.

(b) The court may make a substituted judgment under subsection (a) of this section only on the basis of clear and convincing evidence that the disabled person would, if competent, decide to withhold or withdraw a life-sustaining procedure under the circumstances.

(c) Evidence of the intentions or wishes of the disabled person regarding the withholding or withdrawal of a life-sustaining procedure that might otherwise be inadmissible may be admitted, in the discretion of the court, if it is:

(1) Material and probative; and

(2) The best evidence available.