Be very very careful here. My resaech indicates that joseph Arnett was the son of John W. Arnett, the son of Thomas Arnett, the brother of John Arnett who married Rebecca Comer

John Arnett & Rebecca Comer had only two sons that lived in IIllinois, Thomas, who livved most of his life in Macoupin CCounty, Illinios and Peter Cartwright Arnett who lived in Morgan County Illinois.

John's brother, Thomas had several sons including Joseph, John W. and Thomas B. Arnett