I agree; it could represent unresolved anger towards someone in waking life, a need to have power over other people causing feelings of being under their control... they may be angry at someone (possibly opposite gender) like a boss, teacher, colleague or even a parent - finding the source of this unresolved anger in waking life may stop the dreams and help them to move on.
Like Marcia said, councelling may be the way to go if the source of the anger is not clear - or it may be a simple case of being sick of a teacher (or whoever) telling them what to do all the time, recognising and accepting this will help a lot.
Rape in dreams, and in waking life, has nothing at all to do with sex; it's all about control, or being controlled.
Hope this helps.