Supporting a Patient with Grief and Loss

A 45-year-old male patient is undergoing treatment for stage IV lung cancer. He has been experiencing significant physical decline and emotional distress due to the nature of his prognosis. After the patient's latest follow-up appointment, he expresses to the nurse feelings of hopelessness and despair, stating he wishes he could go back and change the decisions that led to his illness.

In the context of grief and loss, which nursing intervention should the nurse prioritize to best support this patient during his time of coping and adaptation?