It is assumed that Elizabeth, Susanna and James Brown are the children of Thomas Brown.
Elizabeth, Susanna and James all appear on the 1850 census in the household of Isaac and Margaret (Brown) Cole. Their surname is listed as "Brown." Susanna married Absalom Leach in 1850 and Margaret's husband Isaac was named on the marriage bond.
Did Thomas Brown pass away prior to 1850 with the result of Margaret serving as guardian of her younger siblings?
[S32] The Church of Jesus Christ of Latter-day Saints, FamilySearch Family Tree, (http://www.familysearch.org), 11 Mar 2017 (Reliability: 3).
"Kentucky, County Marriages, 1797-1954," database with images, FamilySearch (https://familysearch.org/ark:/61903/3:1:939K-YF9Y-5F?cc=1804888&wc=QD3Q-W4N%3A148181301 : 30 June 2016), > image 696 of 953; Madison County Courthouse, Richmond.