Henry’s time traveling continues to function as a metaphor for his grief. That he is consistently pulled toward the day of his mother’s death indicates his simultaneous fixation on and repulsion from this defining formative moment. It’s something that causes him relentless pain, and he won’t be able to begin to heal unless he confronts that pain, which is why something—either the more powerful forces that govern the laws of the universe and Henry’s time traveling, or perhaps his unconscious mind—continuously draws him back to the moment of the wreck.