All you can do is support her and listen. All she can do is control what she can control…train, workout, play tournaments this summer. Keep the coach updated, continue to build a relationship with him/her. Do the summer workout plan the coach prescribes.
I don’t mean any of this is a harsh way…I am not sure what her (or your) expectations were, but no matter what school/team she chose, she has to earn playing time. The tryouts are a little hiccup, but she is used to competing, no?
Even if the coach who recruited her had stayed and there were no tryouts, she would have had to earn playing time. Then, she would have to be prepared the following years for potentially better freshman and/or transfers to join the team. Coaches are ALWAYS trying to get better players than the ones they have.
As I said above, I know this is stressful. I have two college athletes, and help HS athletes thru the college recruiting process, so have seen and experienced a lot thru these athletes. Someone always wants their spots, no matter the level, from D1 to NAIA to JUCO. It is constant and relentless pressure to deliver results, all while being a student. I wish her good luck and I know you will support her in every way you can.