You can sue in small claims court, but I think it is clear you won't win.

You are not pro se. You represent the estate, and you must be a lawyer to do that.

The law doesn't regulate dating. Your parents do.

Respectfully, that is a question for your lawyer.

I can think of a few potential crimes here, although I am not sure the state would ever pursue it.

You have no grounds to sue them. If you have charges pending, hire a defense lawyer.

The dealer is not responsible. Go through your own insurance.

IMO the bill is purely your responsibility, not your neighbors.

You cannot file an appeal, as you are not a party in the case.

She can get in trouble from the cops, and she could get in trouble from you.