That's a very sad situation with no good way to solve it. The man has already proven that he'll show up there despite being forbidden by law to do so. Responsible parents won't keep paying money to send their kids to a school that has to go on lockdown repetitively due to a specific revengeful guy. If the teacher stays, the students will leave, and then they'll have to lay off other teachers. Since it is a church school, I hope that they've offered her money and support finding a job through their benevolence fund.