To a degree it depends on who initiated the NE posting. It can be either the line manager, trying to get a replacement posted in, or the medics doing what they think is best. I had a person working for me posted NE to the unit PSF (the individual is TG1). After a period and with some intervention from the subjects LM the person was posted back into their original post.
Does your chum trust her LM? Can she speak to them? After that, as already suggested she should go to PSF and, if necessary, the medics to clarify/support her case. The critical point here I think is what loyalty the LM is willing to demonstrate to keep a good person on the team.
OTH if your chum is a waste of space and oxygen thief etc what would you do given a god sent opportunity?