I agree with the couple others that this seems like SOP for those who show invalid/no ID. However, if she really did bring ID (which I'm not doubting--I believe her) then that is seriously sad. It could happen to me next. Even worse, I'm Deaf, so communicating would be very hard.

I strongly recommend you refer your friend to TSA's Got Feedback. Have her be specific, try to mention names/appearances if possible, and additionally, advise her to write both her Congressperson and the airline, threatening an end to business travelling through said airline if this kind of behavior by TSA is going to become more and more common.