See following, this could be Chatham & Mary's son. Its possible you could get info from his S.S. application. Or if you know who handle his funeral or place of Chatham's death the funeral home there should have place of burial. on Death certificate.
U.S. Social Security Death Index 1. Chatham FULKERSON - U.S. Social Security Death Index Birth: 6 Jan 1895SS# Issued: TexasDeath: Jul 1967.