A key question that should be considered by any management coach is whether or not the client is coachable. If the answer is no, then there is no reason to go further.
I see a similar situation in disagreements. There the question is whether or not both parties are willing to discuss the subject in a polite manner so that the differing areas can be identified, facts can be evaluated, and possible areas of agreement can be pinpointed. In essence, the goal is for each side to understand the other person's position.
If either or both sides adopt a strategy of beating down the other side and refusing to hear counter-arguments, then there is little room for discussion. It is not a conversation. It is an attack.
The current social climate provides many examples of the attack mentality. That is a shame. Even if there is reason to suspect that little or no agreement will be reached, there is more to be learned via the conversation route than there is in a rejectionist mode.
Perhaps even a great deal more.
Avoid those who seek compliance more than conversation.