I can comment from personal experience that my wife lost her job teaching Physics at a private 4-year (for the undergraduate degree), not-for-profit, accreditted long-standing (ancient) university in the USA (yay, Boston) with good reputation, despite her excellent teaching reviews from her undergraduate students. They did not renew her contract in the fall just before the Accreditation Review committee was due to visit the University.
Details: she had a terminal Master of Science in Physics, followed by ten years in the defense industry, followed by a Ph.D. in a different field. She taught as an adjunct for a few years before being offered a real position, but was let go because the perception that a Masters level in the field being taught would be seen as a negative by the accrediting board, even with a Ph.D. in a "neighboring" hard science field. She tried to argue for her position to no avail, as they said that they could not risk losing their accreditation. She did not want to take a step back down to teaching as an Adjunct Professor at the same institution again, so they parted ways.
It may be very difficult for your friend to get hired with a Ph.D. in an "outside" field. It may not be just; but that is what happened. They continue to use adjuncts to teach $>70$% of their class-load for undergraduates.
Of course, I must add that you should always apply for a job for which you think you are qualified.