Jim's mother has manipulated him for so long that he doesn't think he can stand it anymore. Or has she? Katie suggests that Jim question this and turn it around until he can see the difference between what his mother says and what he thinks she means.
"When we believe that someone else is our problem," Katie says, "we're insane." As Jim explores his own self-manipulation, he revises the story of his mentally ill mother and discovers that devoting himself to someone else's happiness, before he has found his own, is hopeless.
In the course of this poignant dialogue, Katie says, "Let love kill you". As we follow Jim into clarity, we begin to understand what she means.