what do I do about my lazy irresponsible business partner?

I own a corporation with two other partners and one of which is just flat out irresponsible. He missed two critical meetings this morning because he was hung over; then he refuses to admit that he did anything wrong, later he questions what took place in the meeting. This isn't the first time he has let us down and now he thinks that we are talking down to him and attcking him when we tell him anything, what should I do?