I went through a similar phase, well with the spooky horse phase that your friend seems to be having. You could try to get your friend riding a VERY mellow horse for a while, that's what i did, so that she gets her confidence back. You could also advise your friend to take lessons from a trainer who's is very straight forward with their thoughts on her riding. I know how it feels to want to say something to friend in order to help their riding but not really be able to say what needs to be said. You could also have your friend walk her horse around everything that scares him/her in order to get him/her used to it's surroundings, as well as get your friend to ride in what your friend might think as a safe area, in this case probably a fenced arena.