The ruling on a woman whose child fell into a swimming pool and died without her knowledge

A woman asks and says: My son was with me in our rest area, and the door of the swimming pool was closed. I did not realize until he had fallen into the pool. He was one year old. Is there anything required of her?
No, as long as he was far from her and she did not cause it, she owes nothing. But if she had left him with her...
Q: He was with her, and the pool was nearby, but she knew that the pool door was closed. However, the child’s brothers might have gone and opened the pool?
A: If Allah wills, she owes nothing as long as she did not neglect her duty.