IF you're still looking for this info, did you contact the Collin County Genealogical Society, www.rootsweb.ancestry.com/~txcolcgs/
about his obituary or death certificate? I know the Collin County Clerk's death records start at 1903 so that won't be of any help.
His parents' names might have been on his marriage license.
William M. Boren
Born: 19 March 1787 in Pendleton, Union, South Carolina
Died: 10 Feb 1878 in Collin, TX
Father: James Boren b. 1768, Salisbury, Rowan, North Carolina and d. 1826 Hempstead, Arkansas
Mother: Nancy Boren Mun, b. 1754, Virginia and d. 1851 in Reagor Springs, Ellis, TX
Source: Bland Family Tree, Ancestry.com, however, there are no sources for William so you'll need to prove these are his parents.
Most larger libraries provide free access to Ancestry.com if you have a local library card.
Also there is information about William in findagrave.com.
Have you found his birth certificate? I don't know anything about where they're kept in South Carolina.
The Bowen Family Tree has a copy of the marriage bond between William and his wife Julia and a land record too.