If he's not doing anything other than not drinking, one month is a great time for all of his anger and fears and resentments to surface. He'll continue to blame other people and situations for his own behavior as his ego doesn't allow him to see that he is the problem.
Drinking is but a symptom of alcoholism. Alcoholism is a word for a huge ego with an inferiority complex and the real problem is the person, not the alcohol.
Friends and Family of Alcoholics - SoberRecovery : Alcoholism Drug Addiction Help and Information This forum might help you a bit more.
With love & hugs,
~SB