I was confused in understanding the requirement. Please correct me if I'm wrong - "A worker had used foul language for which he was served a show-cause notice with the same language used therein. There's no denial of the use of such language by the worker, but now the worker wants to sue his employer for inputting such language in the show-cause letter."
Though it's highly unprofessional to use such language in official letters, I'm wondering how a case can even be built upon this. Another instance is when the person suing has himself admitted or at least not denied using such words, and instead of rectifying the situation, the worker is thinking of suing.
I would strongly recommend this worker to immediately stop the idea of suing his employer on these grounds. Instead, if he has used such language, he should apologize and try to improve the entire work environment.