Using familysearch.org for research, I think I might have found the death certificate for George W. Thomas.
When Joe Jack Thomas registered for the World War I draft he was living in Mineola, Wood Co. TX.He gave his birth date as 8 January 1891, birth place, Marietta, OK.
In trying to find George W. Thomas I used the basic search for an individual, giving his name, his birth place as Texas, and I guessed at his birth as being 1860-1870. I found a link from the Texas Death Certificates, 1890-1976, for a George W. Thomas, residence Mineola, TX.
You can click on the link and get the transcribed information.In order to view the death certificate you will need to register with a user name and a password.It is easy and free, and the image gives a little more information.
The information was given by J. J. Thomas, address Mineola, TX.George W. is shown as born 1864, no month or date given. Born in TX, his father’s name is shown as J. J. Thomas.No information on his mother.He is listed as a widower.The burial place is listed as Mineola, TX.He died 22 May, 1916, in the Baptist Sanitarium, Dallas, TX.Cause of death can be seen on the death certificate image.
I still could not find this family in any census, that I could be sure was the right family.