What is the proper etiquette at a viewing from one family member to another?
First, I am very sorry for the recent loss of your Mother. I understand that this is a difficult time for you, and I am also saddened that your niece did not approach you at the viewing.
As for etiquette, I think this is just more about basic caring and compassion within the family when a loved one passes. Unfortunately, our own families can be difficult throughout the funeral process, and it can bring out the worst in us. Should your niece have approached you and/or hugged you? I would say yes – that is just how you show someone you love that you care about them and are supportive of them. Why your niece chose not to approach you, I do not know. Her point about just being there is a sign of support is basically true, but it applies more to friends and other people not as close to you than it does your immediate family.