I don't know about your state, but it can sometimes be very difficult to actually remove a child from any and all schools - especially if there is an IEP in place or limited alternatives.
A lawsuit against the county would seem to be a slim shot. You'd have to show that the county knew that this was likely to happen and that they recklessly endangered staff or students at the new school by placing her there. But, then, did the COUNTY place her? Or was it the school district? It can be come a little convoluted.
However, I presume the child was charged with a crime. If so, restitution for damages will likely result. If mom and dad cannot pay restitution, then it is doubtful they would be able to pay a civil judgment. So, are you willing to pay for a civil attorney hoping you will win and then hoping they have the means to pay any medical bills or pain and suffering? (Note: A split lip is not likely to be a big moneymaker, so you will likely have to pay an attorney up front ... ask yourself, will you even get your attorney's fees back in a win?)
- Carl