Reality of Hemingway

I read this following article. : life.time.com

In this article, Hemingway's real humanity is disclosed.
I was surprised to know that he spent his days drunk and had unsettled state of mind that he could not control his temper, in the early 1950's, when The Old Man and the Sea was written.
And he committed suicide by shotgun at the last.

Although I haven't read the book until the end, the entire story seems to have a calm atmosphere, and the characters seem to moderate and stoic, too.
I wonder why he acted like that in reality and wrote a story in completely different attitude.
Did he want express his inner world in the story through the old man?

Of course, I am not sure about his real intention, but I am sure that I can read the story with more interests by knowing its background.