Looking for Thornhills IN Texas

I have been researching my father's family. The last name is thornhill. My grandfather was born in Texas and lived for a time in Mexico. My father was born in Arizona and went back to mexico and then was raised in San Antonio where he went to school and then on to Sul Ross college and then joined the army aircorps. He flew in WW2. I am looking for information on his Father John Dix Thorhill. My grandfather was in construction. Any information that could be given to me would be a great help.