Can you Help us!!!

Could you please help me find the gravesite of my GG Grandfather, Wm.H. Johnson,  who died in West Texas in about 1916? He, his wife, Marion  (Mary Ann?),and their children lived in Garza and Knox Counties

Here is a  photo of my grandmother, Mollie Kate Johnson Sessions, who, with her brother are standing next to their father's (Wm.H.Johnson's) tombstone.
Please e-mail any information to bensessions@yahoo.com  Blessings and Peace, Benj.Street Sessions    Or Email Me, Gloria