Who is Beth and Christopher Dick from Valis and what is their importance?

Beth is Horselover Fat's wife. Christopher is their five-year-old son, whose life is threatened by an undiagnosed and potentially fatal inguinal hernia until God through a blinding flash of pink laser light discloses the defect to Fat in time for successful surgery. In 1976, Beth leaves Fat, taking beloved Christopher away, intending to return after Fat kills himself. This abandoment is the reason for Fat's second suicide attempt.