While this story probably has more to do with the married relationship, I note that the immediate problem was the non-payment of gambling debts. There are money lenders (okay, the better word would be "loansharks") in every village and they are not people you want to mess with at all.
A very good thai friend who has lived in Chiangmai for the last 10 years owns a small (1 rai) parcel of land with his brother (a farmer) near the Laos border. The brother, without consulting my friend,
borrowed 50,000 baht against the parcel from the local loansharks, the brother having told them that my friend consented to the loan. My friend finds out about the loan (and the fact that the brother is not making repayments) when he was visiting the home village one day. Even though my friend had nothing to do with the loan - and told them he never consented to it or received any of the money - threats were made and my friend is very fearful and almost sure that the sharks will find him in Chiangmai and re-arrange his face/body. He has moved his residence once just because of this fear.
Whether the creditor is named Corleone or Somchai, you really don't want to mess with these people. As for the posted story, it sounds like the family probably did it (but don't for a minute think it couldn't have been the lenders).