what Laurie said is good
here is one other suggestion which has worked in our cases sometimes
((don`t ask a alcoholic to do something-most won`t...))
tell them,hay,you`re in charge of the coffee...you`re in charge of the setting up of tables etc
the approach is everything sometimes
we have had Christmas parties in the past where we got a caterer and had a signup sheet to signup and one or two AA`S took up the money for the Christmas dinner(we had a deadline too)...8 bucks a head,if you wanted to come and was broke,the group or a person sprung for the meal for you