They have a lot more information about what OP thinks and has told them about the situation, which may or may not accurately reflect the reality (I’m not trying to call OP a liar or anything, it’s the old thing about there being 3 sides to every story- yours, theirs, and the truth.)

They also probably don’t know much more about the law and how it pertains to OP’s situation than you or I do. I wouldn’t expect a therapist to be any more knowledgeable about employment laws than I would expect a lawyer to be knowledgeable about psychology, or that I would expect either of them to be about wastewater treatment, it’s not their field.

There’s also the issue of why the therapist thinks op should pursue it.

Do they think it’s because OP is likely to win their case? Again, I don’t think they’re necessarily in a great position or qualified to say one way or the other. OP needs to consult with a lawyer to know if it makes sense for them from a legal/financial perspective to try to pursue this.

Do they think it would be good for OP to have this opportunity to confront their former employer, to try to hold them accountable, get justice, etc. because they think it might bring OP some sort of closure/catharsis? That could certainly be a valid reason, but at the end of the day, it kind of falls on OP to make that judgement call, would it be worth the time, energy, and money to go to court over this, or is it something they can just move on from? And in case they don’t win, what then? Would just having the opportunity be enough for OP whether or not they win, or would a loss make OP feel even worse, leave them right back at square one or worse, and still needing to find a way to deal with it?

Are they genuinely suggesting OP pursue it, or are they saying it to spur OP to think about these kinds of things themselves and make a decision-any decision, because it needs to happen now, 3 months isn’t much time left.