Please, no matter your age, if you travel sign up for travel insurance. Like house insurance...you hope your house does not burn down but if it does....! I believe there are also policies that cover all your travel away from home for a year and if you are doing multiple trips it may be cost effective rather than pay trip to trip. Also, as we age , consider signing for the policy that covers preexisiting conditions...high blood pressure...have a heart attack....some companies would call that a preexisiting condition! I also recommend EA+. It is not insurance (does not cover medical, trip cancelation etc) but they will handle the situation with and for you in the event something happens. We have this policy for travel (not for when traveler is at second home). Don't know about you but as we age even the slightest issue seems overwhelming to us....lol. If current couple had this policy EA would coordinate care and also arrange transportation back to USA.
As to Medicare...the couple in current situation should get copies of all bills with details. Medicare may cover some or all of the medical expenses because it is an unforseable emergency.
Prayers for this couple.