by John Carman
    Life Goes On (ABC), 7 p.m.: A soft-edged family drama about construction foreman Drew Thatcher (Bill Smitrovich), his wife Libby (Patti LuPone), their daughters Paige (Monique Lanier) and Becca (Kellie Martin), and son Corky (Christopher Burke).  Tucked into the story lines is the fact that 18-year-old Corky has Down's syndrome.  So does Burke, the young actor who plays him.
    It's one of the few distinctive new series for the fall.  The family setting is believable, the conflicts are steeped in reality, the light touches are deftly dabbed onto the dramatic superstructure, and the cast is exquisite.  The decision to cast Burke is an advancement for TV, and he delivers with affecting directness.  Life Goes On rewards viewers with a rare glow.  If viewers find the show, that is; the time slot, opposite "60 Minutes," is one of television's toughest.