To be honest, all joking aside, if he gets a good lawyer, he can take her to criminal court for Fraud. Providing he saved all his receipts and text messages between him and the "wife". Then put together a timeline and present evidence and then she and her husband will have some explanation to do in criminal court.
Chapter 3: Offence of Cheating and Fraud
Section 341. Fraud
Whoever dishonestly deceives a person with the assertion of a falsehood or the concealment of the facts which should be revealed, and, by such deception, obtains a property from the person so deceived or a third person, or causes the person so deceived or a third person to execute, revoke or destroy a document of right, is said to commit the offence of cheating and fraud, and shall be punished with imprisonment not exceeding three years or fined not exceeding six thousand Baht, or both.