Final answer:
The nurse may infer that the postpartum patient is showing signs of postpartum depression, as indicated by poor eating habits, sudden crying, and difficulty sleeping.
Step-by-step explanation:
Based on the symptoms described by the patient's partner, the nurse might infer that the postpartum patient is experiencing symptoms consistent with postpartum depression (PPD). These symptoms include a lack of appetite (not eating properly), sudden crying spells, and difficulty sleeping. Postpartum depression is a common condition that can occur after childbirth, affecting the emotional and physical well-being of new mothers. It's important for the nurse to conduct a thorough assessment and possibly refer the patient for psychological evaluation and support.