Final answer:
The nurse should recommend seeking professional help to cope with feelings of uselessness when a middle adult client's children no longer need them.
Step-by-step explanation:
When a middle adult client expresses feelings of uselessness because their children no longer need them, the nurse should respond in a supportive and empathetic manner. Option 4) 'You should seek professional help to cope with your feelings.' is the most appropriate response. It acknowledges the client's emotions and suggests seeking professional assistance to navigate through the emotional challenges of this life transition. Professional help can provide the client with coping strategies and support to rediscover their sense of purpose and find new fulfilling activities or roles.