In New York, a health care proxy is a legal document appointing another person (the agent) power over your health care decisions. Most choose to appoint a family member or trusted friend and this person makes decisions about health care if someone loses his or her ability to make these decisions on their own. For example, if you were to be injured in a car crash and be in a coma, your health care proxy would have the legal authority to speak to the doctor and make decisions about your care. It’s important for anyone over the age of 18 to appoint a health care agent.