Hi There, It's nice of you to be checking on this for your sister. Family support is really important. I have experience with hypnotherapy. I will tell you it's not like the Vegas show where you're out compeltely and they make you cluck like a chicken. It's about teaching you how to do autohypnosis so you can control your physical/emotional responses as well as doing depp hypnosis to put auto suggestion in your mind.
I found it very beneficial. I still use the skills I learned in therapy. I am pregnant right now and can't take any medication so I have to use these skills to tolerate the pain. It also helps you to remain calm and balanced in your life instead of getting stressed out. I had six months of hypnosis for pain management before my last pregnancy and then during the pregnancy I had extra for labor preparation.
I was very calm while in labor. I felt it, believe me, but I wasn't screaming and crying and grunting. Then when my son came out he was so mellow he didn't cry for two hours. He was always a quiet happy baby that slept well right away. So I believe it can work.
If your sister is nervous at all about going because of the idea of it, the therapist would be more than happy to let someone go with her as a chaperone to make sure she knows what's happening.
I would think hypnosis would be very difficult to do as it would be hard to concentrate over the pain. I also wonder about biofeedback as this to me would probably induce stress trying to learn to relax and get yourself under control so the machine does not go off with some noise to notify you that you are not doing a good job. This sounds like me on the verge of insanity. However, I applaud anyone who has the guts to try this. I am afraid that it would overload my circuit as I am already overwhelmed with all the symptoms. (TT)