Cletus was introduced in season 1 as Boss's cousin in Money to Burn.
In "Road Pirates" of season 2 Cletus mentioned his mama. Mentioned her again in season 4.
In "Enos Strate to the Top" of season 3 Cletus was called Boss's 3rd cousin twice removed. (It might have been Hazzardville Horror. I have it marked down as the second episode but I don't know if I counted Carnival of Thrills as one episode or 2).
Hughie showed up in Arrest Jesse Duke in season 2.
Jamie Lee Hogg showed up in the first ep of season 4 as Boss's nephew....Boss's baby brother's boy.
Season 6 said Dewey is Hughie's older brother.
As I recall, Boss's twin Abe didn't have kids. Is that right?
There wasn't any family info given when Boss's big daddy showed up.
Silas Hogg was Boss's uncle and like a second father to Jesse.
Boss's cousin is Big Dan Hogg of Rapaho County.
Boss and Abe were born April 6 1926.
But none of this answers Skipper's question.