Criminal Law Questions? Ask a Criminal Lawyer.
Der Customer - The worst thing your friend can do is talk to the cops so tell him not to make any statements to anyone. If he is charged with a crime he will need an attorney and if he cannot afford an attorney the court will appoint one. Under no circumstances should he make any statements to anyone until he is represented by counsel. It is possible he could be arrested but it is more likely he would be charged and order to appear on his own recognizance assuming he does not have a criminal record. I can't predict what the cops or the prosecutor will do in a specific case but since this is a "white collar" crime and there's no danger to the public the chance of an arrest is less than it would be if there was some type of violence involved.
At this point, unless he can afford an attorney, he can't do anything about what the sheriff or the prosecutor may do so he should do nothing and he should call anyone, except of course an attorney. Keeping silent at this stage of the proceedings is the most important and only thing he can do. Every defense lawyer in America will tell you the same thing.