My Dad died of Colon Cancer...
One thing that helped me was finding a Hospice Grief Group (even if your family member didn't use Hospice you are welcome) and going to their group. And there is no charge.
Just being with people who knew what I was going through helped so much. I felt so alone because my Mom and my sisters and brothers were all going through their own grief and pain.
I would recommend Hospice to anyone - both for my Dad and then for those who have a loved one who has died.