When Mr. Mallard dies, why do his friends and Mrs. Mallard's sister take care to break the news to Mrs. Mallard as gently as possible?

Due to the somewhat unstable emotional and physical health of Mrs. Mallard at the time of her husband’s passing, it becomes clear that the sister was careful in breaking the news to her due to the fact that they wanted to ensure that she was not pushed to a further level of health degradation as a result.