I would recommend she look at being a stripper first. At least in the states, it is far more respectable and safer.
Make sure that she insists that clients use protection.
Have a safe place. It's best if she can get her own hotel room or studio, and some sort of basic security system (e.g. "If I don't phone so-and-so within x days, come and see if I am ok).
Don't accept clients that she dislikes because of a gut feeling.
Don't do it too long. Stop ASAP when reasonably free of debt.