Visitor medical polices provide coverage for any new medical conditions and travel-related emergencies as defined in each individual policy. Travel medical insurance policies typically do not cover treatment of pre-existing conditions, routine medical check-ups, or preventative care. While the policy does not cover pre-existing conditions, it may cover any other unexpected medical situations as per the policy's terms.
Learn more about visitors' insurance: Visitors Medical Insurance
There is no need for a power of attorney to visit medical facilities in the US by the insured. Here is a good read about travel insurance for persons age 80+ visiting the USA : Travel Insuracne for Seniors Age 80 Years and Older
Insurance rates are regulated by law. You can't find the same insurance plan for a lower price anywhere else