Friends and Family Members are under Medicare.

Sorry to reply in English.  Using iPad handwrite keyboard is not easy and very time consuming!  Google translate is even worse!

You dont need to enroll Medicare thru any agent.  You can enroll online from the provider's site.

All the knowledge can be learned by research done online.  You should use English sites to learn.  Chinese sites too much misinformation.  just sayin.

As I mentioned, writing the long long post is I feel obligated to help people with same ethnic background. 

Regular Medicare 不保在國外短期居住或旅遊時的醫療開銷

Each plan is different.  You need to enquire the plans available IN YOUR AREA.  Insurance plans are VERY LOCALIZED.  If you understand anything on statistics and autuary,  you would understand WHY insurance plans are so localized.

Humana's Medicare Advantage cover Emergency Care when out of plan area, including out of country.  You need to pay first then submit your claim with the supporting documents.

Canada in the long past cover what you asked, but the expenses became too high to bear.  Canada removed the coverage at least 15 or more years ago.  We see many Canadian snowbirds each Winter.  They all buy short term medical insurances as far as I know.