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Since you know when and where Thomas died, you can obtain a copy of his death certificate, which should show the names and birth locations of his parents.
I see you haven't posted on the Coryell Co, TX forum, yet. I recommend you do, also check the Coryell Co, TX GenWeb site, some GenWeb counties are putting their cemeteries online. Post your query on that site, too. Also, ask if anyone has a copy of a county history, and would they check for any possible information on this family. Getting your query out there in as many places as possible may up your chances of making a connection, with all those children, there may be other descendants out there researching this same family.