Son's Wish to Die, And Mother's Help, Stir French Debate
French debate emotional issue of assisted suicide following death of Vincent Humbert, 22-year-old paraplegic who wrote book asking for right to die and passed away after mother administered overdose of sedatives; Marie Humbert acted on third anniversary of car accident that left her son paralyzed, mute and blind; photo; she is taken in custody and then released and hospitalized, having won enormous public sympathy for her campaign to help her son and legalize euthanasia (M)