Final answer:
The nurse would suspect a grief reaction in a 12-year-old patient if they observe changes in the child's physical health status. The correct answer is option C.
Step-by-step explanation:
The observation that would cause a nurse to suspect a grief reaction in a 12-year-old patient during a health history interview with a family is C. Changes in physical health status. Grief reactions often manifest through physical symptoms such as changes in eating and sleeping habits, weight loss or gain, and somatic complaints.
These changes can indicate that the child is having difficulty processing a loss and is displaying symptoms of grief. The other options, such as structured family flexibility (A) and familial listening and self-disclosure (B), are more indicative of a healthy family system that could support a member through a grief process.
Alteration in family dynamics (D), while potentially related to a member's grief, is more about change in how family members interact with each other, which could be for reasons other than grief. In contrast, changes in physical health clearly signify a possible stress response.