Very confused by expectations

I am recently widowed which has been a difficult adjustment. My husband's son's wife has been estranged from my husband and me and his son can not stand up for himself. We rarely saw them and in 27 years and never invited to their house or out to dinner. Since his father's passing, the son only corresponded to my emails regarding distribution of assets. My husband left each of his kids nearly $1M. 4 days ago their son was killed in an accident. In the obituary there was no mention of my husband predeceasing the grandson and there was no mention of me as a surviving step grandmother. My husband and his X have been bitter towards each other since their divorce 30 years ago. After so many years of anxiety regarding their behavior and lack of acknowledgement, I am not compelled to attend the funeral as I didn't get opportunity to know him due to parents' estrangement. As an unwelcomed family member, I really would not rather go. Any thoughts?