Lies, deceit, creating mistrust are his ways now.

Obi-Wan:  ”Do you believe what Dooku said about this ‘Darth Sidious’ controlling the Senate? It doesn’t feel right.”
Yoda:         “Joined the Dark Side Dooku has. Lies, deceit, creating mistrust are his ways now.”
Star Wars II: Attack of the Clones

The Plasticity of Details

Upon hearing your writer friend tell a story in public, you will eventually be moved to announce (or, if you’re a really great friend, merely think), “That’s not what really happened.” The story you once knew so well, having been present or perhaps even personally involved in the events, is changed while you listen. Nearly all the details are fine, or maybe most of the details of the story are there, or perhaps only the spine of the actual event is sticking out for you to recognize. This can, for the unprepared, be disconcerting.

You need not fret as neither you nor he are in the process of losing one’s faculties. Rather, the very thing that makes someone a great creative writer is also what makes him a rather poor historian. They have imagination in abundance. What was once a good story about him renting a hotel room in Paris with a decided slant to the floor becomes in the retelling a) a hotel room with a slant so bad that the furniture had to be nailed down to keep it from sliding; b) a hotel room with a 20 degree slant that, if you weren’t paying attention (such as when you first woke up in the morning), would make you stumble into the sink; or c) a hotel so off kilter that when he opened a window, the breeze was able to move only one curtain, the second one hanging so far from the edge of the window.

Your friend, while not telling the literal truth, is not actually lying. He is spontaneously filling out the story into its best form, making it into what it could have been. While it was pretty surprising to catch one of my roommates covered in blue from ankle to knee, from another roommate’s pilfered bottle of Nair hair remover, it would have been far funnier if I’d had enough sense at the time (instead of thinking about it a day later) to hand her my own bottle and remind her, “Get that toe hair, too, while you’re at it.” So, in your own “that’s not what really happened” event, realize that he honestly remembers the event much as we see ourselves delivering that killer one-liner: as good (or bad) as it could have ever been.