Is your mediator familiar with alcoholism/addictions?
Here's a quote from a thread I was reading:
Originally Posted by
NYCDoglvr 
When you're lashing out at an active alcoholic you're really just talking to a bottle. Alcoholics live in various shades of a blackout with shades of gray. Their anger and lies are about fighting anything that comes between them and their drug of choice. This is a mental illness characterized by extreme compulsion to drink. I say this as a recovering alcoholic (26 years) who essentially missed the 1980's. My best friend knows my story better than I do.