Re: Caribbean schools
^
If that's true, then that's incredibly foolish on your friend's part. Caribbean graduates, and all other Americans who go abroad for medical school for that matter, are at a distinct disadvantage when it comes to applying for residency in the US, and are seldom able to match into the most competitive spots. They're (rightly) seen as applicants who were unable to get into US allopathic or osteopathic schools, and their applications are often given even less priority than those from foreign applicants.
As for the matter of being able to do clinical rotations at hospitals across the US...you're allowed to do that as an American medical student too...its called doing an "away rotation," and you actually have more options as a student at an American school, as most university affiliated medical centers don't accept foreign students. Generally, the only hospitals that take foreign students for clinical rotations are less desirable community and government hospitals.