We have a show with a gl door that seals it and my son filled it up and broke the shower door. What's next?

I have no idea how or why he thought of doing this but the gl door cost 2000 dollars and the amount of water that flooded into our bedroom and flooded into the kitchen, the damage was insane. We had a drywall guy come out give us an estimate on how much it would take to fix everything and he told us 4500. Why would my son do this? He is 10, and we are thinking of enrolling him in a private school away from everyone.