Getting her to the physical therapist is important especially in the early stages following the injury.
What they have her do will assist the healing process, and remaining active through the healing time.
Did the PT give her anything to complete at home between sessions?
If not I’d contact them and ask what to do between sessions.

Have you watched episodes or the webinar about the lumbar spine?
Increasing your knowledge about how things work and interact will help you understand more about the situation.