Unpaid internships should not be deemed unauthorized employment.
The above is intended only as general information, and does not constitute legal advice. You must speak with an attorney to discuss your individual case.
Hello. If this is truly an internship related to her coursework and not employment, then she may do this. Sounds like should be okay. Good luck to her. http://www.nejamelaw.com/articles/l1-visa-preventing-surviving-request-for-evidence.html
An unpaid internship related to her coursework should not present a problem. I would also suggest that you consult with an experienced immigration attorney for professional assistance and guidance.
This answer is of a general nature and should not be relied upon as final, nor is it intended as legal advice. A consultation with an experienced attorney is always the best way to go.