head down with babys back against mums front is the ideal presentation.
Back to back, as GS says, means the contractions are felt in the back and this can take longer and be more painful.
when your daughter isnt on all fours then perhaps get her to sit (if she hasnt got any complications with pelvis) astride a dining chair facing the back. This can help baby turn as well.
Bless her for getting nervous, theres not really a lot she can do now except wait and see how it all goes, but i do know how she feels :)