June told Dorothy Bencher that she was afraid that the children would be taken away from Sheila because of her behavior. If children are abused it's not the relatives that decide if they should be taken away, it's the authorities. During the conversation at the dinner table Sheila was delusional and took it as a direct threat. What is irrelevant is whether there was a real possibility that it would actually happen.
How do we know what, if any, delusion Sheila was under? Had June been speaking of Sheila's past behaviour -albeit the hospital and social workers involved with the children's care had ruled out abuse- or her behaviour at the time of the call?