A health care power of attorney, sometimes called a health care proxy, is like a regular power of attorney, except it specifically gives the agent the authority to make medical decisions on the testator’s behalf. A health care power of attorney generally goes into effect if the person becomes incapacitated per at least one doctor’s medical opinion. This can be if someone develops a condition that affects their decision-making abilities, like a traumatic brain injury or dementia, or if they are unconscious or in a coma.