Hi Joe
I had a problem similar to that of your friend and obtained the requisite retraining (as well as an effective little gadget which helped me to see when I was doing things right - I'd rather not go into details) from a specialist physiotherapist. This physiotherapist deals with all sorts of neurological / muscular troubles arising in that general area of the body (including women in the aftermath of childbirth and other such traumas!)
I should mention that the device that she gave me had electrical leads that I did not have to use. However, I understood from her that these are used in some difficult cases for stimulating the muscles electrically to increase tone.
Hope this has not frightened you or your friend too much.
Merle