This my not be the same thing, but I think that grandparents do have some rights in relation to their grandchildren in some circumstances.
I say this because I knew someone whose daughter had a child out of wedlock and social services were pushing for the child to be adopted. And the child's grandmother objected and said she would bring up the child. Social services, I was told, tried to convince the grandmother, at the time in her early sixties and on her own, to "be reasonable" and sign a piece of paper declaring whatever it was, and she refused. And she took the child in and brought the child up.
So it seems she did have some rights, else the child would have been adopted against the grandmother's wishes. I don't know the whole circumstances, but I do know that the child's mother was not dead, as the mother and child met at some later time.