I am not a doctor (but I am a Sonographer, so I work in healthcare directly), so take this advice or leave it, but it's my 2 cents. I would say if it's only "lightly" prolapsed, and is not causing any definite problems like pain or incontinence, then go for it. Just make sure she's aware of how she's feeling there, and if there's any change, see the doctor.
Also, I tend to recommend Kegels for most problems of that kind. You know, the exercise that involves squeezing the vaginal muscles, hold, relax, repeat as much as possible. Especially have her focus on tightening these muscles when doing exercises that make her tighten the core. Otherwise tightening the core while having the vaginal muscles relaxed can exacerbate the problem with downward intraabdominal pressure. Kegels will help with leakage issues, and is likely to at least prevent further prolapse.
*Disclaimer: I am not a doctor, nor do I play one on TV. Any advice given herein is meant solely as amateur advice and is not to be taken as any medical endorsement, yadda, yadda, yadda. . . . .

Hope she continues the program and has great gains!