Hi there Leann and thanks for reaching out. May I ask if this is the first time this has happened that she can remember, and if she is under 28 years old?
In either case, if she is unable to control the seperation of the astral body, i would suggest a regular meditation schedule in which she grounds the energy of her astral body to her base. That being said, I would also suggest in her meditations to let her astral body fly freely for at least 15 minutes a day within her meditations. I do feel that the spiritual body sometimes is wiser than the rational mind and physical vessel, and perhaps there is some work needing done within her astral form.
I short, yes, work to ground it, but at the same time, don't deny the occurrence, for it will only strengthen its need to happen.