Depression. Using psychiatric treatment.

Hello dear, It is normative to feel a void in a person's life after loss of partner. It is indeed one of the most stressful life event as per the mental health scientific literature. Whether or not your father needs treatment will be decided by the time since death of your mother and his inability to cope, severity of his symptoms, impairment and distress caused to him, history of prior mental illness, available support system etc. Hence I would recommend an assessment ti be done for him by a trained mental health professional which are a Psychiatrist, Clinical psychologist, or a Psychiatric social worker. Whether he requires medication or psychological intervention or a combination or even no treatment at all should be decided after an assessment. Hence my suggestion for you is to please seek a consultation with a mental health professional near you for comprehensive assessment and further management. Hope this helps you.Best wishes for your father's mental health well being.