In "Waiting Around To Die," Townes Van Zandt is a lost soul bouncing around through life seeking distraction from the awareness of his own mortality. He seeks that distraction first in gambling and drinking, then in codeine. In some ways the song echoes Van Zandt's struggles with substance abuse, but the character he portrays in the song is fictional.
The character comes from a harsh upbringing of abuse and abandonment. After his mother ditches the family, he has his heart broken by a girl in a bar in Tuscaloosa, Tennessee. This accelerates his downward slide, leading to robbery, prison, and finally the grim comfort of addiction.
Van Zandt did indeed struggle with alcoholism and heroin (not quite codeine but also an opiate), but he came from brighter circumstances. Some would go so far as to say he was privileged. His family had proud Texan roots and his father was a corporate lawyer. Van Zandt attended the University of Colorado at Boulder in 1962 and the University of Houston in 1965.
Still, despite some differences in detail, the song's character seems to mirror Van Zandt's psyche. In the song, Van Zandt never outright says he's destroying himself in order to hide from the pain of his nihilistic despair, but that's the gist of the choruses. They change slightly from verse to verse, but each time they imply that life itself is just a period of waiting around to die.
Rather than wait around for the Reaper to come, Van Zandt's character figures he might as well pummel himself into oblivion with booze and bad living.