Bankruptcy discharges can be revoked for up to one year after they are granted for various reasons not involving fraud, and of course fraud's statute of limitations doesn't even begin to run until the fraud is discovered (or should have been discovered). Which is not to say that there has been any in this instance. I have no idea whether these people have played games with the system or have simply experienced good fortune on the heels of misfortune.
If they have committed BK fraud, there can be a reward. But you need to do some sleuthing.
If you smell a rat what you can do is to contact the office of the US Trustee for what ever district their bankruptcy court is in. If you can find out who the case trustee was you can let him know too. Many times bankruptcy fraud is discovered on tips such as yours.
It is not uncommon for a person to come out of bankruptcy and to buy new luxury cars. Texas is one of the states whose laws caused most of the issues in the 2005 bankruptcy reform laws. Texas have VERY generous exemptions, especially for the real estate. Although I am not from Texas, I have heard that the entire parcel of property is exempt without regard to value.
In Ohio the exemption just went up from $5,000 top $20,200. No one is flocking to Ohio to take advantage of our generous exemptions. On the other hand prior to 2005 celebrities relocated to Florida and Texas to file for bankruptcy.
You might feel jealous, or even cheated, but I would not be surprised if everything is on the up and up.
Before you take a step like this that could expose you to civil liability if you are wrong, I suggest you consult with a Texas bankruptcy lawyer to see if he thinks anything is amiss.
Contact a bankruptcy attorney and have them get you a copy of the bankruptcy petition filed by this person. they are public information. Then you can review the disclosures and determine if your suspicions are bassed in fact or if there were other disclosures that could explain the observations. Perhaps they took money out of an exempt account that would explain what you are observing.