A: Your business dinners are obviously very different to those I attend! The role of the NED is multifaceted and certainly embraces ensuring good governance as well as being a trusted and objective sounding-board for the CEO. It is not the role of the NED to know everything about the other directors but, needless to say, any signals that something is amiss or potentially amiss is clearly salient. It is not an easy call for you and I'm sure your own moral compass will inform whatever decision you make.
My advice would be that you should express your genuine concern at the CEO's behaviour and its effect on his leadership role. It is a difficult choice, but you should take the necessary action, possibly mentioning it to the chairman. Or you may wish to keep this between him and you, perhaps asking if there is anything you can do to help him if he regards his drug-taking as a problem.
Maybe the CEO misread the signals but it was after all a private dinner and he got it wrong. Very wrong.
A: First of all, don't be surprised if none of you gets the position external candidates can look very appealing when faced with upsetting the status quo and damaging the business.
You clearly respect your two colleagues, having worked with them for a number of years, so you know how each other tick. Of course you don't know for a fact who is in the running, you may already be the preferred candidate so this is not the time for an all-out war.
But any behavioural changes from you that are not natural to you will be glaringly obvious and, secondly, there is no doubt that whoever is making the decision will be very sensitive to the fact that whichever of the candidates is not chosen may choose to exit the business.
I am surprised how often I find that even very senior people who would like to rise to the next level do not share their ambition with the relevant people. Without being pushy, why don't you find the opportunity for a coffee with the chairman (or the decision maker) and gently say that you are very interested in the role.
If you have a question for Sue, email her at firstname.lastname@example.org.