Conversation so far:
How did the program help Bill W.?
It helped him obtain sobriety.
How long was Bill W. in the program?
What did Bill W. accomplish while in the spiritual program?
In 1938, after about 100 alcoholics in Akron and New York had become sober, the fellowship decided to promote its program of recovery through the publication of a book.
How did Bill W. help others with alcohol?
Wilson returned to New York where he began having success helping alcoholics in what they called a nameless squad of drunks in an Oxford Group there.
What was the name of the book Bill W. worked on?
The book was given the title Alcoholics Anonymous.
Did Bill W. invent Alcoholics Anonymous meetings?
A seemingly unplanned meeting in Akron, Ohio in 1935 between Bill W. and Dr. Bob, future founders of Alcoholics Anonymous, began the program for recovery.
Any other interesting facts about Bill W.?
Wilson and Marty Mann would go on to found what is now High Watch Recovery Center, the world's first alcohol and addiction recovery center founded on Twelve Step principles.

Question: how long was he sober?
Self-contained rewrite: How long was Bill W. sober?