1900 Census Justice Precinct 3, Wilson, Texas
Name			       AgeMary E Heathcock	       56
John A Heathcock	       33
William C Heathcock      18Leona Heathcock	       16
Margaret Heathcock	       13
Alva Heathcock		         9
Ethel Heathcock	         6
1910 US Census of Bexar Co., Texas, ED78 sht 13B Dwelling 205, Family 218Heathcock, William C., Head, M W 29, S, Texas, Louisiana, Louisiana, Farmer 
Heathcock, Mary E., Mother, F W 60, Wd, 12/6, Louisiana, Mississippi, Louisiana 
Heathcock, Ethel, Sister, F W 16, S, Texas 
Holland, Stell, Nephew, M W 10, S, Texas, Texas, Texas
On his WWI Draft Registration card (12 September 1918),
25 his birthday is given as 27 December 1878.  He was 39 at that time and gave his nearest relative as his brother, J. H. Heathcock.
1930 Census of Wilson Co TX
Name         	AgeStell Holland        	31
Hattie Holland     	27
Inez Holland     	  4
Collins Heathcock	13   cousin
Will Heathcock     	50   uncle
The Social Security Death Index gives William C. Heathcock, 452-86-6242, San Antonio, Bexar Co TX, with birth date of 14 Dec 1880 and death date of 15 Jan 1969.  His death certificate indicates that he was never married.