How to defend against the case?

My father works in an insurance company, two years ago a client came to him to get the insurance of his late brother but his documents were incomplete. So, my father suggested him to a person (who sits outside the courts) to attest/complete his documents. That person (who sits outside the courts) made the fake documents with the fake signature of a judge. Then after few days when those documents were sent to the judge for verification that judge found his fake signatures on the documents and he (judge) filed the FIR against my father and the person who made fake documents. My father along with the person who made fake documents was arrested and stayed at prison for 15 days. Now court is proceeding to judgment soon and we are afraid of the judgment that they will punish my father as well. Therefore, I want your advise on this that whether my father will be punished on this or not? If yes then who long he will be punished and is there any way to defend my father against this case? your advice will be appreciated. Thanks in advance.