However, when such symptoms persist beyond a few months' duration, they may represent the onset of a major depressive episode. Although it is much more common for grief symptoms to resolve within a few months, the stress of a significant loss can sometimes precipitate a major depressive episode. Such a progression - from grief to clinical depression - is more likely when individuals have previously experienced a major depressive episode.
In my experience, grief reactions tend to be at their worst within the first few weeks after the loss - then symptoms show gradual but persistent improvement. When grief precipitates clinical depression, I have found that symptoms are often more profound a month or two after the loss than they were initially.
Most primary care physicians are quite familiar with the diagnosis and routine management of major depressive disorder. If you have questions about your father's condition, I would recommend that you have him consult with his physician. If differentiating between grief and clinical depression is difficult in your father's case, his physician may refer him to a psychiatrist for a more specialized evaluation.
If your father's health care providers believe that he is experiencing the onset of clinical depression, they will likely recommend some form of treatment - either medication or psychotherapy, or both. If, on the other hand, his symptoms are believed to reflect a grief response, such treatments are less likely to be helpful - although grief support groups, and other social supports, may be quite helpful.