From his website;
When I Get to Heaven, which brings a healthy dose of levity to what might have been a grave situation. Prine revealed in 2013 that an operable form of cancer had been found on his lung. Fortunately an operation proved successful. The diagnosis followed a 1998 surgery for neck cancer, which made him give up smoking for good.
That was 20 years ago and I still miss cigarettes, he admits. If somebody lights up, Ill go stand next to them after they’re up so I can get that initial blast. So Id written this chorus about having my favorite cocktail and having a cigarette thats nine miles long. I kept thinking, Where the hell can I do that? The only place I can get away with that it is in Heaven because theres no cancer there. So, the chorus dictated the setting of the song. I made up the verses around that.
A very interesting theology. Sad he apparently was so deceived.