Ask your friend to quiet the job. ...search another one and this time don't lie with the company. If you are applying or joining any reputed firm then they have contacts for background verification also now companies were sending direct e-mail to HRD for verification of Employee. Even I am also using direct contact method in my company for employee verification.
So, either make good relations with HR or tell the truth at the time of interview to get the job .
All the best .
Your friend has committed acts of forgery , he must consider his current employer to be very "large-hearted" if he is released
without registering any case. He must remember that short-cuts lead to painful situations and have an impact in the future
He must own up everything to his current employer & remember this experience throughout his life.