Responses
Nah. I just think they needed a playmate and nurse for their sickly daughter that’s why they took Yiren in. They stopped supporting her once they got Yiren. It’s also possible they simply supported the lady just so they could take in Yiren. With her background she could become a useful card later. In addition to keeping her as a servant basically and locked away they also tried to ensure she didn’t the mentality to ever disobey. Those don’t seem like the actions of someone who cared.
It's kind of surprising that the reason Count Chase kept Yiren was to keep his sister safe. Like, it's pretty out of character from the man we know him to be. I guess he used to love his sister? And he even used to support her too. I wonder what happened? He was a brother who cared about his sister so much that he put is own wife and child at risk. There must be some other reason why he changed.