Cal. Probate Code § 4766

A petition may be filed under this part for any one or more of the following purposes: (a) Determining whether or not the patient has capacity to make health care decisions. (b) Determining whether an advance health care directive is in effect or has terminated. (c) Determining whether the acts or proposed acts of an agent or surrogate are consistent with the patient’s desires as expressed in an advance health care directive or otherwise made known to the court or, where the patient’s desires are unknown or unclear, whether the acts or proposed acts of the agent or surrogate are in the patient’s best interest. (d) Declaring that the authority of an agent or surrogate is terminated, upon a determination by the court that the agent or surrogate has made a health care decision for the patient that authorized anything illegal or upon a determination by the court of both of the following: (1) The agent or surrogate has violated, has failed to perform, or is unfit to perform, the duty under an advance health care directive to act consistent with the patient’s desires or, where the patient’s desires are unknown or unclear, is acting (by action or inaction) in a manner that is clearly contrary to the patient’s best interest. (2) At the time of the determination by the court, the patient lacks the capacity to execute or to revoke an advance health care directive or disqualify a surrogate. (e) Compelling a third person to honor individual health care instructions or the authority of an agent or surrogate.