Nonsense

"Listen to what you're saying!" Song Yi wore a stern expression. "That's your sister, not a murderer."

Song Yi did not know about what had transpired during this period, so in his eyes, Song Yin remained the obedient daughter who never caused trouble. 

People often clung to their beliefs and were resistant to change, despite any amount of persuasion.

Over the years, Song Yin had masterfully played her act in front of Song Yi, and with Meng Yu's support, she had successfully cemented an image of obedience and fragility in his mind. 

This image was deeply ingrained and couldn't be erased overnight.

Song Kai's eyes were wide with shock. "She's already done such a thing, and she even said that she wanted to kill Little Sister. Is it wrong for me to want the truth?"

Song Yi found himself in a moral dilemma. On one hand, he empathized with Song Yin's current state of delirium, but on the other hand, he also desired the truth.