I am not related to this line but found some Grable information for you. Mineral Wells, TX is in Palo Pinto County. Below is a link to the Palo Pinto County Archives. Scroll down to the bottom to the Search field and put in the name Grable. You will find links to birth records which include Billy Carl Grable, b. 8 April 1929. You will also find links to births of his siblings. His mother was Alberta Christian, his father was William Paul Grable.

http://www.rootsweb.com/%7Eusgenweb/tx/palopinto/palotoc.htm

Do you have access to census records? The 1930 Texas, Palo Pinto Co., Mineral Wells City shows the family as it was at that time indexed with their father's name shown as Paul Grable.

I did not try to go back further to find Paul Grable's family, nor Alberta Christian's, but you could probably find them.

The Social Security Death Index as found at www.familysearch.org lists Alberta Grable, b. 9 June 1902, d. 10 June 2001. The death residence locality lists Fort Wolters, Mineral Wells, Salesville, all in Palo Pinto Co. TX.