Yuchun Xu’s condition goes beyond lack of physical ability and communication. That obviously has repercussions in her own life, but her disabilities also tax her family to the limit. It essentially turns her family back into caretakers, well after the age when they finished raising children.
The exhaustion piles up, both from the lack of sleep, and the frustration at dealing with an unresponsive person. What keeps them going on is knowing that if they stop, she will get even worse.