I believe that Joseph McHenry (b. 1818, South Carolina) is a brother to John McHenry (b. 1808, South Carolina), both in the 1850 Sparta, Randolph County, Illinois census. Joseph and wife, Mary (Adams), with children Jane, Samuel, and Hugh, are listed along with Louisa Dobbins, who married John McHenry in Randolph County on 11 Nov 1850.
I'm trying to find a connection of two McHenry's, John and Joseph, to Daniel Murley McHenry (b. abt 1775, Kentucky; d. 20 May 1844, White County, IL)-possible sons? John F. McHenry is listed as administrator on the probate records of Daniel Murley McHenry, and there are a John and a Joseph who were both land owners in White County circa 1838.
Daniel Murley McHenry married Elizabeth Jones in 1802 in Warren County, KY. Many researchers, myself included, have verified two sons, William McHenry, and Peter Jones McHenry, who both settled in Henry County, Illinois, but the censuses of 1820 and 1830 say there are at least 4 more sons and 5 daughters.