Same family and now is a good time to start your research. Your grandfather had an older sister Bertha Gregory (22 Jul 1879 - 13 May 1957) who died in Jasper. Logon https://familysearch.org/ and setup a "free" account with username/password. You'll need that to view/print death certificates. Next, click highlighted "Death" on the homepage. Enter Texas in Death Place box then click highlighted "Parents". Enter Irons in "Father's Last Names" box. Enter Willie Phillips as the mother then click search. To view their father's certificate, delete the parents info, enter J E Irons as the person, then click search.