He should consult a criminal defense lawyer.
The question raises a significant question: If he paid in cash, such that he thought that the cash change left on the bar was his, and he managed to leave the bar without talking to anybody or being detained, how did the police find him? If the answer is that he paid with a credit card, that's going to be a problem for him. If the answer is that he's a regular, then it would be a bit surprising that the first thought of the staff at the bar was that he took the money on purpose.

