This is a very believable and wonderfully done story that explains much of canon Petunia and Vernon, as well as Dudley.
Lily appearing at the hospital and conjuring a bunch of flowers as if she were helping by doing so and then leaving Petunia to do the scut work - well, I think I would have been a touch bitter after that display myself.
Not a side of the coin I had considered much, very interesting indeed, L