Kate's gaze darkened when she saw the phone in Erin's hand. She was on it again, threatening Kate by telling lies to their mother, so she'd get a small heart attack that might be fatal because she had a weak heart and a constantly weakened body.
Kate didn't understand how Erin became this cruel to their mother. Erin never had to feel any grievance, except when Kate reported her father, who ended up with him spending time in jail, breaking their family apart in the end.
She felt guilty for ruining their family. Kate understood that Erin needed to be comforted the most since she was the youngest, so Kate tried her best to fulfill any demand that Erin wanted, whether it was to do an easy task, such as bringing her a glass of water, to something harder like doing her homework or giving Kate's part-time salary for Erin because she wanted to buy a new toy.
