How to write a rebuttal letter - good resources?

[Qwe]

I have been asked to help write a rebuttal (no, not me) for wrongful dismissal. The subject (person A) was assumed to have authority over an area which he did not. Specifically: The norm is he would be assigned above the GM of one of the activities, however this particular GM had previously been assigned above him and had repeatedly voiced he would only do the GM position if person A were not in his chain of command. On paper he was, but in reality he reported all actions and information directly above person A. The GM was terminated for sexual harassment. Now person A is being dismissed because if initial minimization and subsequent cover-up by the directors above person A. He feels this is not fair and requests assistance in writing a letter. Any good resources out there? I am not a lawyer.