Green’s Dictionary of Slang

(orig. US) absolutely everybody.

1865		in J.K.P. Miller Road to Virginia City 6 June (1989) 74: ‘Everybody and his cousin’ here seems to live in a log cabin and mud roof.
1874		Andrew Co. Republican (Savannah, MO) 14 Aug. 4/3: These many attractions will be an inducement for everybody and his cousin.
1879		Cass Co. Republican (Dowagiac, MI) 2 Jan. 3/1: Everybody with his ‘sisters, aunts and cousins’ is invited.
1882		Breckenridge News (Cloveport, KY) 23 Aug. 3/4: The ratification hop [...] was a success. Everybody and his wife, sisters and daughters, and everybody else’s sweethearts were there.
1886		Lantern (N.O.) 10 Nov. 3: Everybody and their mothers-in-law were present.
1888		Semi-Wkly S. Kentuckian (Hopkinsville, KY) 11 May 3/1: Everybody with his cousin was present.
1892		Wkly Intelligencer (Lexington, MO) 1 Oct. 2/5: Everybody, his cousins, his aunts and his mother-in-law was here.
1900		Arizona Republican 10 Nov. 4/5: Everybody and his cousin are finding out that we are the people to trade with.
1901		Boy’s Own Paper 30 Mar. 414: Everybody and his aunt play checkers, as our American cousins would say.
1907		Wenatchee Dly World (WA) 27 Sept. 1/3: They say that everybody and his wife should go to the depot.
1908		Seattle republican (WA) 10 July 4/4: Everybody and his brother are clamorous for the moving of the redlight district.
1908		Beaver Herald (OK) 4 June 1/1: Everybody and his aunts, uncles and cousins were in Beaver Decoration Day.
1909		Spokane Press (WA) 16 Dec. 1/1: Everybody and his cousin has heard of the ‘Two Tims’.
1918		Cayton’s Wkly (Seattle, WA) 27 Apr. 1/3: From an organized labour standpoint everybody and his brother are crazy.
1920		Watchman & Southron (Sumter, SC) 30 June 6/3: Crowded? Well it seemed that everybody, his aunts, cousins, brothers-in-law, grand-parents and grandchildren had started [...] that hot Tuesday morning.
1922		Bisbee Dly Rev. (AZ) 26 Oct. 6/4: Plans [...] for one of the biggest turn-outs in history [...] Everybody and their cousin will be at the park.
1951		M. Spillane Long Wait (1954) 17: Everyone and his brother knows you and we can’t prove it.
1965		H.S. Thompson letter 5 Feb. in Proud Highway (1997) 493: Everybody and his bedbuddy are starting papers and little magazines these days.
1965		R.L. Pike Mute Witness (1997) 67: Everybody and his brother has been calling you every two minutes all morning!
1976		R. Sabbag Snowblind (1978) 146: Everybody and his mother is going to be there.
1982		M. Braun Judas Tree (1983) 167: Everybody and his brother!
1993		Eble Campus Sl. Apr. 2: everybody and their mamas – the entire world.
2022		J. Hannaham Didn’t Nobody Give a Shit 143: Folks appeared to be in that July 4th mood [...] Ev’body an his dog up in here an it’s only the 3rd?
2023		Rayman & Blau Riker’s 137: When they call medication in the afternoon, everybody and their mother gets up to try and get high.