Advice needed legal situation

Hi - my close relative was sitting in her parked car at church and another churchgoer crashed into her with their car. The lady left the scene but witnesses were there who know both parties. The lady later admitted fault and it’s documented. The crash has already been worked through insurance and my relative has been taken care of in terms of medical/car repair.

However, out of the blue the person that crashed into my relative decided to sue my relative for who knows why despite them being 100% at fault. My relative is going through the court process now and we’re recommending to countersue as it has become aware to us that this person has sued/tried to sue people 4 times already. The point of countersuing wouldn’t be for any monetary gain and we are suggesting to have the countersue money be donated and be used as a lesson to stop this lady.

My relative says she doesn’t want to countersue (even with the donate plan) because it isn’t godly but our stance is that this person is going after people (and Christians) in malicious and unethical ways. Even at church.

Is there any advice, stories, or bible verses that i can share with my relative to give them a viewpoint of it being okay in God’s eyes to countersue and donate the money to address this scenario?