“A guy walks into a bar…”  is a typical form of what has been called the “bar joke.” An anti-joke of the bar joke is:
 
“A man walks into a bar. His alcoholism problem is destroying his family.”
 
“A man walks into a pub. He is an alcoholic whose drink problem is destroying his family” was cited in print in 2002. The anti-joke has been printed on GIFs.
         
 
The Man Who Fell Asleep (August 17, 2002)
A man walks into a pub.
He is an alcoholic whose drink problem is destroying his family.
 
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OT Jokes from Germany
Philamental
2/18/04
Dunno bout you guys, but I found these very funny this morning ...
Phil

> Knock, knock.
> Who’s there?
> The police. I’m afraid there’s been an accident. Your husband is in
> hospital.
>
> A man walks into a pub.
> He is an alcoholic whose drink problem is destroying his family.
 
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880 days till AATA opening
Count Bazzu
2/18/04
>The following are apparently jokes from Germany, that have been translated
>into
>a language we understand more.
>
>They tend to lose most of their comedic effect after translation:
 
A man walks into a pub.
He is an alcoholic whose drink problem is destroying his family.
 
Something Awful
Jokes With Realistic Endings
Tuesday, Apr 12, 2005 by Nick “Mayor Wilkins” Dunn
(...)
A man walks into a bar.
He is an alcoholic whose drinking problem is destroying his family.
     
Google Books
A Year in the Life of The Man Who Fell Asleep/
By Greg Stekelman
London: Friday Books
2006
Pg. 128:
A man walks into a pub. He is an alcoholic whose drink problem is destroying his family.
 
Urban Dictionary
Anti-Joke
A joke or riddle-joke that starts like a standard joke or riddle-joke, but then turns out not to be a joke at all. The surprise element thus becoming the joke.
A standard joke turned into Anti-Joke:
A man walks into a bar. His alcohol problem is destroying his family.
(...)
by dkgemini May 24, 2006
   
Twitter
Paul Cotton
‏@pwcotton
Anti-Jokes are the new humor: A man walks into a bar. His alcohol dependency is destroying his family.
9:00 AM - 18 Aug 2008
 
Twitter
dekaf
‏@dekaf
A man walks into a bar. He is an alcoholic and it is slowly destroying his family.
8:15 PM - 11 Jan 2009
 
Twitter
¿Jaime?
‏@Jaime__e
ANTI JOKE OF THE DAY: “A man walks into a bar…. His alcoholism is destroying his family.”
11:49 PM - 28 Dec 2009
 
tickled
June 16, 2014
25 Of The Best Anti-Jokes Ever. #12 Is Gold.
BY BLUESTAPLES
(...)
12. A man walks into a bar.
His alcohol dependency is tearing his family apart.