Jane Wyatt, the lovely, serene actress who for six years on "Father Knows Best" was one of TV's favorite moms, has died, said her publicist. She was 96. Wyatt died Friday in her sleep of natural causes at her home in Bel-Air, according to publicist Meg McDonald. Her death also was confirmed by Bernard Johnson of the funeral home Gates, Kingsley & Gates Moeller Murphy Funeral Directors.