Final answer:
The appropriate response is to explain to the parents that managing pain is crucial in sickle cell crises, even if the child is sleeping, and to involve them in discussing the pain management plan.
Step-by-step explanation:
When caring for a client who has sickle cell anemia and is in a sickle cell crisis, it's paramount to manage pain adequately, even if the child appears to be sleeping a lot. Sleep can sometimes be a way for patients to escape the pain, but this doesn't necessarily mean they are not experiencing it. Therefore, the appropriate response to the parents would be Option 3: "Even though your child is sleeping, it's important to manage the pain appropriately. Let's discuss the plan together." This response acknowledges the parents' concerns, implies continued provision of care, and invites them to participate in their child's care plan, which could include understanding why pain management is necessary in sickle cell treatment.