What traumatic events have occurred in Johnny Merrimon's life that make him a troubled boy in the novel, The Last Child?

Because of the abduction of his twin sister, Alyssa, abandonment by his father, Spencer, and his mother, Katherine's, addictive relationship with the despicable Ken Holloway, Johnny is a hyper-vigilant 13-year-old who double-checks locks on the doors, drinks and skips school, and distrusts adults.