Two months after knowing that his son was suffering from leukemia, a 45 year old father presents with sleep deprivation, lethargy, headache and low mood. He interacts reasonably well with others, but he absented himself from work. The most probable diagnosis is :
The information in this question is :

Stressor (knowledge about medical disorder in a child).
Mild depressive symptoms → low mood, sleep deprivation but normal social interaction Symptoms within 3 months of stressor.

The diagnosis is adjustment disorder.
Depression
Psychogenic headache
Adjustment disorder
Somatization disorder