I would love to see a definitive deep dive into the life of Camilla's paternal grandmother, Edith Marguerite "Margot" Harrington Shand Tippet. Accounts of her actions as a mother vary drastically, and at least some of them - including, traditionally, the most prominent ones - are definitely untrue. I have an impression the last decades of her life consisted of poverty and loneliness, but I would love to be wrong.
She's frequently been described as abandoning her son after her divorce and her move to the US with the golf course designer. The Daily Mail has said this, at least one book I've read has said it, and apparently - though I haven't read it - Bruce Shand gave the impression that this was the case in his memoirs. Whether he meant to do so or whether it's just that his wording accidentally gave the wrong impression, I'm not sure.
However, passenger manifests definitely confirm he sailed into New York with her, arriving in first class on the
Cedric in 1921 and the
Carmania in 1923 (thanks, StatueofLiberty.org!). Accounts agree that the Depression ended his stepfather's design career, and the family returned to England so he could take up much more modest golf club administration work.
Sources seem to agree that Bruce's father Philip was always absent from his life, but his education - beginning with Rugby School - was paid for by Philip's parents. It's frequently claimed that, after the return to Britain, he spent more time with his paternal grandparents than with his mother. This
might explain why he might have been turned against his mother (if he indeed was), however his stepfather's
Wikipedia page claims that the Tippets and the elder Shands remained friends, and that his paternal grandmother even moved in with his mother and stepfather after being widowed.
I haven't seen anything to indicate Bruce's stepfather wasn't a decent guy. He served his country as a soldier and seems to have worked hard. However, he wasn't financially successful. Sources also agree that Bruce's mother was left very badly off after her husband died in 1947. Wikipedia puts the value of his estate at 666 pounds. She spent her life thereafter about an hour away from her son's home, and I would love to think she was included in his family circle.
Her character and her relationship with her son are definitely murky, and it would be nice to see this cleared up.