I was watching the news with my wife about some Thai guy was sentenced to death for rape/murder (or something similarly unpleasant)

And my wife said "And he also has to pay XXXXX baht to the victims family", I asked how he was supposed to do that seeing as he would be in jail, and then dead?

She said "Well his family [parents] will have to pay".

Is this true that if your (adult) son/daughter does something bad, then you as the parent would have to pay fines that the son/daughter could not pay?

I was a bit puzzled, and asked if the reverse was true; that children would have to cover the debts of deceased parents, and my wife also said that she thought so.

Is this true or is my wife just really misinformed?

I was watching the news with my wife about some Thai guy was sentenced to death for rape/murder (or something similarly unpleasant)

And my wife said "And he also has to pay XXXXX baht to the victims family", I asked how he was supposed to do that seeing as he would be in jail, and then dead?

She said "Well his family [parents] will have to pay".

Is this true that if your (adult) son/daughter does something bad, then you as the parent would have to pay fines that the son/daughter could not pay?

I was a bit puzzled, and asked if the reverse was true; that children would have to cover the debts of deceased parents, and my wife also said that she thought so.

Is this true or is my wife just really misinformed?

No, not true. Only limited to the estate of the deceased that the debts have to be settled against but not to the assets of the survivors.

About 130 years ago in Thailand, an English citizen of Indian heritage had a debt to a Thai man. Back then, Englishmen were covered by English law, not Thai law.

The Englishman died, and the Thai creditor went to his home to take his daughter into a brothel to pay off the debt. This was standard practice then. The English "embassy-equivalent" told the creditor that as English people, they were covered by English law, and that although Thai law may allow this, English law does not.

The Thai creditor lost his loan.

From the book: History of Anglo-Thai Relations