Hi Vin_Ind,
You have stated that your wife resigned the job in a school due to misbehaviour of the Admn, legally speaking there was no need for resigning the job, since she could have brought it to notice of Head Master/Head mistress /Principal or to Secretary / President
of the school highlighting the conduct of the Admin. Anyway,since she has resigned, she has to submit a detailed letter showcasing all the facts that has led to her resignation and if there any colleagues of her stand as a witness/support to this incidence will have a added advantage may help her reinstatement in the school or Management may reconsider its notice period based on the situation.
In case it is sexual harassment, you can file a FIR against the concerned Admin in the jurisdictional Police Station based on the facts you present they will definitely take action against that Admin.