12yo broke arm at tumbling, had surgery will need another, numbness in hand, had OT, has nightmares approx $80K, who is responsible for payment?

Broke both bones in arm while tumbling with a spotter at gym, had 1 surgery, will need another, has had OT, possible permanent nerve damage, and has nightmares my insurance covers most. Total will be @ $80K. My out of pocket will be @ $5K. There is some type of insurance at gym that we pay a $35 fee. Who is liable? She missed 3 weeks of school plus all the therapy appts 2x a week.