Subordinates have to learn on their own that they can make decisions that should be made by their boss when he or she is a no-decision manager. It is never taught in business school. I call this situation, aphonic acknowledgement. Once they have decided to make the decisions of their boss, they have a number of other decisions to make themselves on how they are going to work in this new, unknown environment.
Decisions to make
Subordinates must choose how far they go in decision-making for their no-decision boss. They can stay within their chosen freedom zone, but they can go much further. Many subordinates will limit decision-making to those directly related to their own department. But I have seen subordinates take over as the unofficial leader in place of their no-decision boss, and take decisions in the departments of their colleagues. Of course, they have no formal authority or legitimacy, but the position is there for the taking.
Finally subordinates have a choice: to inform or not to inform the boss of the decisions they are taking. No-decision bosses have no preference over whether they are informed or not by their subordinates. They know intimately what is going on in their organisation, so will learn of the decision sooner or later. What is important for them is not what has been decided, but that something has been decided. However, it is good practice for subordinates to inform their no-decision boss of the decisions they have taken. This is not to get their approval, because naturally none will be given, but more out of courtesy (to the person who is after all the boss) and to maintain good relationships with them.
Things to look out for
But this is not all, subordinates need to watch out for other colleagues that are also in aphonic acknowledgement taking decisions in place of their no-decision boss and make sure that they do not venture into their territory of decision-making. They can also test whether to help colleagues who have chosen to stay in resignation, frustration or conflict with their no-decision boss and see whether they can take some of the decisions.
Subordinates that take decisions must learn to protect themselves in the event that a decision made by them is not liked by their no-decision boss’s boss. If the decision turns out to be a bad one, the no-decision boss will attack and blame their subordinate. If the decision is a good one, the no-decision boss will take the credit for it and never acknowledge the subordinate. It will be up to the subordinate to decide what form their protection should be. It is ironic however, that many of the protection tactics for subordinates are the same as those used by their no-decision boss in their survival strategy, and so surprisingly they can learn something from their no-decision boss.
Finally as subordinates of a no-decision boss, they must also be aware that any career advancement in their organisation is now over. Their no-decision boss benefits greatly from them taking his or her decisions and is therefore not going to let them go. Promotions within the organisation will be actively resisted and transfers to other departments will not be allowed. In essence subordinates careers will not move forward while working for a no-decision boss. The only way to get out is to resign. The boss may not take decisions, but the energy put into keeping decision-making subordinates in place is surprising.