Romanian Doctor

Physicians cannot automatically become RNs or NPs in the US -- medicine and nursing are two entirely different disciplines. Foreign-educated physicians, just like everyone else, have to complete a nursing education program approved by the state BON (Board of Nursing) in order to be eligible to write the NCLEX-RN exam and pass the exam in order to get licensed as RNs. NPs are educated at the graduate level (Master's or doctoral programs), and pass a national certification exam in the specific NP specialty. There are "direct-entry" Master's programs that accept people with at least a BA/BS in another field and combine basic nursing education with an MSN program, and many of those programs offer NP specialties. That might be an option for your friends.

There has been discussion here in the past of a few "MD to RN" abbreviated nursing programs that are set up to prepare foreign-educated physicians to be eligible for RN licensure in the US, but I believe most of them are located abroad. I'm sure there is more information available about that that I don't have, that you (or your friends) could find if you looked.

I imagine that the best bet for your friends would be to talk to the BON and any nurse practitioner programs in their area and ask what requirements they would have to meet, whether any of their previous education would transfer, etc. They are not automatically qualified to become NPs, or even "basic" RNs, because they were practicing physicians in their home country.

Best wishes for their journey!