Got Fired for theft Civil Demand Notice inquiry

My son was fired from his job this last Monday from Walgreens for theft. I'm just worried and not sure what to expect. I read several issues regarding the law firm Palmer, Reifler & Associates and after reading the articles I'm worried. He is 21 years old and lives on his girlfriend.
This is what is letter states. "Civil Demand Notice" Theft amount $2,500. You are notified that this state has passed a law permitting merchants to recover civil monetary damages and/or penalties from you, and/or your parent or guardian, as a result of this incident. These damages may take into consideration the value of the merchandise (if not recoved in merchantable condition), and any other damages and/or penalties permitted by law. You, and/or your parent or guardian, may be receiving a letter from the Law Offices of Palmer, Reifler & Associates, on behalf of Walgreens, in the near future to recover this civil demand. The civil damages and/or penalties assessed are not in any way inteded to compromise any criminal action Walgreeens may seek as a result of the incident." They did pay him his last check in the amount of $436.00 and he applied it to the amount that he owes. He has no proof, besides the word pd 436.00 owe, $2064.00 on the sheet of paper with no signature of the person who took the money. I had him call the loss prevention agent to get the signed papers from Monday and then a receipt to show he paid $436.00. The lady was not in the office today. I guess that day they said if he doesn't sign the paper they will do further investigation and it could be more money. I know one fact out of the theft is he bought gift cards from a credit card that was left behind and he rang it up himself. Now, I'm not sure of the total. Please help.