Very many medical doctors get advanced degrees (MA, MS, DSc, PhD) in fields related to their research interests so that they can qualify to teach medicine or so that they can conduct research.

A PhD in Internal Medicine would not be anything unusual for an MD who teaches Internal Medicine to have. The question you want to ask is where is it from? The quality of the awarding school is the important consideration.

Now, there are some schools which have, or had, some sort of a weird PhD in medicine. I know little about this, and I haven’t heard of it in many years. But it still wouldn’t have been in internal medicine, not in the US.

So what you’ve got there is either a foreigner, and God only knows what sorts of degrees they’ve got, or you’ve got someone who is trying to gild the lily a bit more than is desirable.

Go call the schools that he’s listed on the resume. I don’t like it.

it is offer at various schools of medicine (and maybe others)

the PhD programs are very narrow fields of study

so yes

University of Barcelona offers this Doctorates program

as do others

UAB