Have you thought what it would be like if a parent turned their back on a child and failed to bond with them? It is a strange, awful thing to happen and leaves the child with a serious and maddening problem.
It is inexplicable to the child that the parent has turned away from them. At the same time the parent now has no interest, no comprehension of the problem the child is experiencing. It makes no sense to the child, it causes a ceaseless anguish. And if there are siblings that the parent seems to find it easier to bond with, then the sense of confusion and distress is compounded further.
How is such a child supposed to endure, let alone thrive? Could an animal in the wild survive like that? Could a plant grow without the sun? The child has a serious problem and possibly not much help to fall back on.