After flying my daughter home from Costa Rico on a Lear on my dime, I became interested in travel evacuation for medical treatment insurance. At the time, Medjet, an Alabama company, was starting in cooperation with Univ of AL in B'ham (UAB) hospital. I happen to know some private pilots who flew under contract for Medjet, and was impressed with the response described by them.
Now, numerous companies provide this service. Under any policy, make sure the patient controls the evacuation, not the company. And your choice is for any reason, not limited to "life threatening" or "absence of available care" at patient's location. Also, include the US in your coverage, not just overseas. One story involved evacuating skier with bad broken leg from CO to UAB for a preferred ortho surgeon. My family has had Medjet coverage for years, and fortunately never needed the coverage.