Overcoming Grief

My father passed away last night. I’m feeling grief over the loss. Not only because he is no longer here, but for all the things I should
have done. He lived on the other side of the country so I rarely got to see him. I didn’t take the time to visit him or call him more often.
He struggled financially and I had no idea how bad things were for him. His failed businesses and financial problems caused him so much stress it literally killed him. How do I use the model to forgive myself for not being a better son?