From what I read you are not with him 24/7 how can you possibly know when and how much he drinks? If you believe what he says you are on the wrong track. "A's" lie, whatever he says mutiply it by 3, you may be a little closer to the truth.
He may be a binge drinker now, this too will lead to daily drinking, the others who have posted here know what they are talking about.
Save yourself alot of heartache--listen to them!