The parents of a child just diagnosed with a chronic illness share with the nurse that they are concerned about the sibling's sudden change in behavior. Which of the following is the BEST response by the nurse?
1. "Her brother is feeling left out right now, but we plan to include him in his sister's care."
2. "Her brother is just feeling left out right now, but he will start acting normal soon."
3. "Her brother is worried about her and is just reacting to his fear."
4. "Her brother is going through a normal developmental stage."