He needs to be careful. I can't say for this particular school, but it's a documented fact that many many students fail out of Caribbean schools, or they can't pass the required exams (that are required of ALL students to get back into the US and get any kind of residency here). So yes, he could certainly fail and have spent a lot of money and time in the mean time.
Personally, I think he needs to find out more before he jumps in. Medicine is a long and hard road for anyone, and would be or will be longer and harder if he goes the Caribbean route. For example, I have been working at this (med school, residency, research years/fellowship and now clinical fellowship) for 9-10 years, not counting undergrad, and I'm still not out and practicing yet. Also I have 130k in debt and this is having gone to school several years ago...the schools are all more expensive now. And I still make 50k/year and work many weekends and holidays, many many more hours per week than your average job. He just needs to make sure, as much as possible, that he'll actually like practicing medicine and that he can stomach the academic stuff before he goes ANYWHERE to med school, including the Caribbean. For example, during my 2nd year of med school I had to sit in a classroom 6-7 hours/day and then go home at night and memorize all the stuff for several more hours/day (and I don't mean just 2-3 hours). And then there will be repeatedly staying up all night, probably with no sleep at all, during 3rd and 4th year of residency and during internship and residency too. Honestly, that part sucks and the only way someone can stomach it and not hate his/her life is if medicine is really one of the few things he/she wants to do in life; it really is kind of a brutal lifestyle in many ways, so not something to get into lightly.