My querie is really did they scatter the ashes on the husbands grave, then inscribe the wording as if she was buried there.
Dale
It maybe that the ashes were scattered at the grave, but the ashes may have actually been interred, rather than scattered, in the grave. If the ashes are interred (and possibly if scattered), permission would probably be needed and there may be a record of that.
My paternal grandmother's ashes were interred in the grave of my grandfather and there was a small ceremony for the interment, but the gravestone says "also of the above" On the other hand my maternal grandmother's grave implies that my grandfather is buried in the same grave as her, when in fact he is buried 100's of miles away.