I think it is his personality but the alcohol magnifies it. This behavior is not directed to just me, I have noticed it in his relationships with family and friends.
I expect this is true, it's his personality and alcohol magnifies it.
Also true: when you hold your ground with a bully they will back down. They may sputter and bluster but it's just talk, like you say. I have a friend who I've learned to ignore when he gets like that.