Final answer:
In the termination phase of group development, the most important activity for a nurse group leader is to assist members in processing feelings of loss as they confront the end of the group experience.
Step-by-step explanation:
In the final (termination) phase of group development, the most important nurse group leader activity is to help members process feelings of loss. This is a crucial step because during this phase, individuals often confront the end of their group experience, which can elicit emotional responses similar to those experienced during the ending of significant relationships. Throughout the group's existence, if the leader has implemented a democratic style of leadership, they have fostered an environment where members can openly discuss and share their thoughts and feelings. As the group concludes, the leader's role transitions to providing support as members express and work through their sense of loss and prepare to move forward independently.