I'm a little confused, was your father buried or cremated in the end? 7 years sounds like quite a short period to exhume a body as I heard sometimes it can take a lot longer to decompose.

Your mother is very philosophical and calm about all this, and her decision probably means the least disruption. It's also very forward looking as there are so many abandoned old graves, it makes one wonder, after ones children or grandchildren dies, who else will visit or tender a grave of someone they've never met?