Hi Usually behavior like these are manifestations of combination of personality traits, coping skills and change in life circumstances (stresses). Sometimes other factors like physical health, family or relationship or financial stresses or even any substance misuse all contribute. Retirement for some people can lead to depression due to total change in their routine, roles, responsibilities, including boredom, feeling of loss of control etc. It is important that your Dad meets a professional. Tell him that as a family you may have to consult someone to develop better bonding and not because he has a problem. Also, keep appreciating his emotional distress with empathy and use words like you understand his feelings without saying anything suggestive of a 'blame'. Advice good lifestyle like yoga, meditation, social outings etc. Regards