I would be surprised if her doctor hasn’t already spoken to her about possible treatments. I know very little about pelvic floor prolapse, but as with any issue affecting the pelvic floor, Kegel exercises are almost always beneficial.
It is important to be sure the Kegel’s are being done correctly, as some women are not sure how to isolate those muscles, and are not always told how to do the exercise correctly.
Here is one website that can help: http://www.mayoclinic.com/health/kegel-exercises/WO00119
It’s important that the exercises not be done as a quick tightening and releasing of the muscles. The muscles should be tightened and held for 10 seconds, then released, for a set of 10, and it’s recommended to do this at least 3 times a day. They can be done sitting or standing. If the correct muscles are being isolated, the person won’t move at all, but if they do, they are likely tightening thigh muscles or abdominal muscles, and this won’t help.
I do kegel’s on my drive to work, it’s almost mindless.
I also do them at my desk at work.
Only her doctor can tell if Kegels would help. Pelvic floor prolapse can be mild to severe. I would really recommend she do some searches online to see what is advised. Of those things I can find, it ranges between Kegels to inserts to surgery, depending on the severity.
I wish her the best of luck!