I do think if the Army is asking questions I would talk to an attorney. See if you can be held responsible even if you were just a friend that knew her whereabouts.
Maybe they the Army might find her mentally ill and give her a medical discharge?? Has she ever had to have anti-depresants, etc.?
I am just makeing suggestions, I do not know the laws etc.
((HUGS)) has to be sooo hard.