Can you believe that I turn 37 next week, yet I've never had any alcohol before?
My father was an alcoholic growing up, but hes been sober for 20 years.So no alcohol for 20 years.
I think after having had a problem with alcohol, being sober for 20 years is more of an accomplishment than never touching it at all.
He did the Twelve Step Program through Alcoholic Anonymous.  We're very proud of him.
I would be as well!  Do you do anything to celebrate his sobriety anniversary? 
Not particularly, but he does help other alcoholics make it through the program.