The older sister was put in an impossible situation! She was forced to lie to her own mother while receiving minimal support or updates from her younger sister. It's unfair to expect someone to carry such a heavy burden in isolation, especially when the younger sister dismissed her concerns and discomfort. The older sister's breaking point was understandable, not a betrayal.
Oh, please! The older sister's discomfort doesn't excuse breaking a promise. She knew the younger sister was in a vulnerable position, yet she prioritized her own feelings and curiosity over her sister's trust. Instead of being a supportive confidante, she caved to pressure and stirred up family drama. Her actions scream selfishness and a desperate need for attention.
While the younger sister placed an unreasonable burden on her older sister, the older sister ultimately broke her promise and betrayed the confidence placed in her. The discomfort of keeping a secret does not justify violating a promise, especially when the younger sister explicitly asked for discretion. However, the younger sister must also acknowledge her role in creating this situation by isolating her sister and dismissing her concerns.