In "Safe Harbor," what does David's reaction to his mother's medical crisis reveal about their relationship?

Throughout his visit, David has had a hard time warming up to his mother, and it is clear that he resents her fragile mental state. She has never really been the "safe harbor" that David needs. Still, when she has a seizure he is terribly frightened and feels very young and alone, indicating that he still needs her and longs for her to keep him safe.