5x23 - Family Ties

When Alex's friend Greg dies in a car accident, Alex is thrown into a state of shock and begins to seriously question the meaning and purpose of his own life. Having been asked to accompany his friend on the fatal trip and refusing because it wasn't convenient, he is overcome by guilt. He tries to fathom why he was spared in the face of such selfishness, and begins to have encounters with Greg's ghost. His family urges him to get help.