I am so sorry that she is dealing with this injury. We also dealt with a bi lateral pars defect last year in our oldest. She was in a brace and unable to lift more than the milk carton for 12 weeks. (the brace was more of a reminder of her prescribed limitations, to both herself and those around her, than to support the injury). There were waves of emotions that came at the oddest times, and threatened to take her down. The only advice I can offer is hang in there and stay the course! We followed the advice to do nothing to a T and a year later my daughter does not have any pain in her back, nor any signs of a lingering issue on her imaging.
She resorted to crafting and invited friends over to join her for projects. We did service projects to help her focus on others. (This had such an impact on her views on life.) We also held board game/card nights for her and her friends to help her have an outlet for her competitiveness. During her time out of gym, she did ask her coaches if there was anything at the gym she could do to help out. She ended up being able to count conditioning numbers and time stretching for her teammates, and it gave her a chance "Be" a part of the team.
I wish your daughter the best of luck in her recovery. Hang in there!