Arterial blockage is usually very severe by the time symptoms develop. Whether more should have been done when he went to the ER depends on the symptoms he did present. You did the best you could. He would not blame you. But, blaming is part of grieving, it is normal...you will grieve in the way you need to grieve. Don't forget the good memories. Take care of yourself, and those around you. ((((hug)))))