I am an attorney in Houston. I have a client who has retained 10% against the general contractor. A supplier has timely filed $100K in liens. As I read the statute, the owner's liability is limited to the 10%. The question is, does the supplier still have a lien on the property?
The legal analysis would start with a review of your client's contract with the original contractor (the contractor who contracted with the owner), and then extend to the nature of the project (residential, homestead, commercial, etc.), and to the notices that the supplier has provided by certified mail, and to whether the owner filed an affidavit of completion.
Retain a construction attorney to evaluate your client's legal situation, and to provide advice.
If your client has complied with Chapter 53 of the Texas Property Code, your client's liability is limited to funds trapped by a proper funds trapping notice, and the 10% retainage, assuming that the owner received a notice of retainage before 30 days had passed from the date that the project was fully complete.
Good luck.