With Peter Fonda in a key role, the message of "A Reason to Live" seems to be that even sticks have feelings. Fortunately for the NBC movie, which airs at 9 tonight on Channel 4, there's a real actor on hand named Ricky Schroder who saves the film just as surely as the youngster he plays saves his father from suicide.

The film flip-flops the trendy TV-movie topic of the year, teen-age suicide, for a story about a middle-aged man (Fonda) whose world disassembles in the course of about a week. He loses his job (because he has too much integrity) and he realizes his wife is having an affair with her boss at the real-estate office. She even invites the guy to the family's celebration of Thanksgiving, which is about as low as a blow can get.

But Alex, the 13-year-old man of the house, played by Schroder, senses how serious his father's despair has become. He notices him making out a will and riffling through old photographs, and he discovers the gun Dad kept in the attic is now missing. Never panicked but deeply anguished, Alex talks to a counselor at a suicide prevention clinic (Bruce Weitz, de-grunged from his Belker role on "Hill Street Blues," in a nine-minute cameo) and then sets out to rescue his old man.

Fonda is bloodlessly anonymous as the father; could one of the reptiles from "V" be hiding under that Hollywood-royalty skin of his? Peter has never come across as a young Henry Fonda. He has always seemed more like a young Robert Vaughn. Now a middle-aged Robert Vaughn. There doesn't appear to be a paternal bone in his body, either, which causes a viewer to wonder how that son of his turned out to be such a mature and intelligent paragon.

As Delores, the wife who beats a retreat, Deidre Hall has to look like she means it when she recites such dialogue as "Give me a little bit of space, please" and, to the husband she is dumping, "You're a wonderful guy -- sensitive, caring." In a way, the emptiness of these two characters works for the movie. They're living in one of those antiseptic paradises in southern California where an absence of individuality gives one a real advantage in life. There's no sociology to the film, though; those who made it appear to share the values of those depicted in it.

Schroder is the only good reason for seeing "A Reason for Living." He's a maximalist among subminimalists. His anxiety and his desperation are so informed, it's a trifle eerie from one so young. Maybe the adult actors decided just to give up and hand the movie to him, since he would steal it anyway. But as written by Robert Lewin and directed by Peter Levin, the movie doesn't offer a lot to make off with. They don't come up with very ingenious ways for cheering up Dad (for one, the son looks up Pop's college sweetheart, played by Carrie Snodgress, and has her pay an awkward visit) or for resolving the conflict.

In fact, in the last half-hour, the situation becomes a shade comical, as the son keeps refusing to let the father alone so that he can do away with himself, and Dad keeps trying to put the son on an airplane out of town so he can be alone with his .45. "You know what they say about kids; you can't fool them," Schroder remarks. You couldn't fool (most) adults, either, with uplift so mechanical, but it's to Schroder's credit that he can carry this ball over the finish line and give it a healthy spiking as well.