Short answer. Yes. Under Article 2016, if the gambling loser refuses or neglects to sue to recover what he lost, his creditors may bring the action themselves. Whatever is recovered is then applied to satisfy the creditors' claims against him, so you can step in when your debtor will not act.
What the law says
If the loser refuses or neglects to bring an action to recover what has been lost, his or her creditors, spouse, descendants or other persons entitled to be supported by the loser may institute the action.
Civil Code, Article 2016 — Recovery by the Loser's Dependents. Read the full provision →
What the law says
The sum thereby obtained shall be applied to the creditors' claims, or to the support of the spouse or relatives, as the case may be.
Civil Code, Article 2016 — Recovery by the Loser's Dependents. Read the full provision →
Why the law lets a creditor step in
Ordinarily, only the person who lost money has the right to sue to get it back. Article 2016 makes an exception for gambling losses because a losing gambler often has no interest in reopening the matter, especially if he is embarrassed or continuing to gamble with the same people. The law recognizes that this inaction can hurt the people who depend on him financially. So it grants a substitute right of action to "his or her creditors, spouse, descendants or other persons entitled to be supported by the loser" when the loser himself will not act.
What you have to show before you can sue
The right to sue as a creditor only arises once the loser "refuses or neglects to bring an action to recover what has been lost." That means you generally need to establish that your debtor was in a position to sue for the gambling loss and simply did not, whether out of indifference, embarrassment, or continued involvement with the winner. You are not creating a new claim of your own — you are exercising the loser's own right to recover, on his behalf, because he has failed to use it.
Where the recovered money goes
A creditor who sues under this article does not simply keep whatever is recovered as a windfall. The statute directs that "the sum thereby obtained shall be applied to the creditors' claims, or to the support of the spouse or relatives, as the case may be." In practice, this means the money is used to pay down what the loser owes you, up to the amount of your claim, rather than being handed to the loser to spend again. Any excess beyond what satisfies your claim would belong to the loser or be distributed according to the interests of others entitled to bring the same action.
This is a narrow remedy, not a general debt-collection tool
This article only applies to money or property actually lost in gambling — it does not give creditors a general right to sue on every claim their debtor is neglecting to pursue. The gambling context matters because the law specifically wants to discourage the kind of losses article 2016 addresses and to protect the people the loser is supposed to support. If your debtor's inaction concerns some other kind of claim entirely, this particular provision would not be the basis for stepping into his shoes.