family law in TX, preventing garnishment of social security for child support

You need to consult with an attorney who practices in the county where the last court order was entered. The Attorney General has a wide range of powers to use to collect past-due child support. If a judgment was taken, even many years ago, it is probably still enforceable. You may be able to reach a compromise agreement with your ex-spouse or work out a payment plan. If you do nothing, you should expect continued trouble because the A.G. has located a source of funds.