"a spin-off of alcoholics anonymous, is designed to provide support to children of parents who have alcoholism"

There is more than one organisation that provides this service, but the most well-known one is ACON (Adult Children of Alcoholics) - dealing with the long-term effects of growing up in an environment full of alcohol. 

Another one is Al-Anon/Alateen - specifically focused on the families of the alcoholics, also for the alcoholics that are themselves not seeking help.