Just because it is nothing to her by blood, doesn't mean the baby is nothing to Camilla. It is the grandchild of the man she has been in love wit for decades, married to for a decade.
Of course Will would wish his mother was there. But eventually people, even children, do move on. Not in the sense they forget her, but they don't have mommy haunting their every move either. Its okay to go on with life, marry and have kids, and be happy without constantly looking to the past.
Why would it dishonor their mother for Camilla to be a part? It doesn't take away from Diana in any way. They have accepted her for years as their father's wife, and made her a part of the family. Why would it be any different with the baby? Children can use all the love they can get.
I know from experience, blood means little to nothing, especially to kids. My Grandma is my Grandma, and if I hadn't noticed my mother called her by her name and not Mom, as she still called her father Dad, I would never have known till older. My mother's mother died when she was a child, and her father remarried ten years later. They were married for 30 years, until he died, and never had kids together. He had six with my bio grandmother and she had three from her first husband. To this day, even with five grandkids and three great-grandkids of her own blood, she doesn't treat any of my grandfather's 11 grandkids and soon to be 14 great grandchildren any different then her own.
