The 1926-1949 Texas Birth Indexes show: Robert Lee Whittle & Mary Lucille Robbins had: Mary Virginia Whittle 1945 in Brazoris county. Robert Alan Whittle 1947 in Brazoria county. The other children were probably born after 1949 so I can not track them to their parents.However I have sent via email a listing of their births and marriages.
From the Social Security Death Indexes Name Birth Death Last Residence Last Benefit SSN Issued ROBERT WHITTLE07 Nov 1922 Oct 1973 (not specified) (none specified) 458-20-6822 Texas
The 1964-1998 Texas Death Indexes show: Robert L Whittle died 1973-10-02 in Harris county. Mary Lucille Whittle died 1995-05-25 in Harris county.
I have found a possible match for your grandfather but you have to get his death certificate or knowledge of the brother Bryant or the parents.This might not be the right family for your grandfather.There are so many Whittles and Robbins in the census records, one has to have additional information.
1930 Red River Co., TX 5 J-PCT (Northeast Part) P207 April 5th #40 Manchester Whittle Robert L head m w 44 mrrd at 24 TX SC TX properitor store " Oua wife f w 34 mrrd at 20 TX TX TX " R. L. son m w 7 sgl TX " Bryant son m w 5 sgl TX