Facing mortality, he chose to keep boldly living life

Elizabeth Edwards, facing invasive cancer, has said that she doesn’t intend to let the disease “be the boss of me.”

That brand of courage is on display in “So Much So Fast,” a documentary about a remarkable young man who’s diagnosed with Lou Gehrig’s disease (amyotrophic lateral sclerosis) but who won’t be deterred from living a full life.

The film, from Academy Award-nominated directors Steven Ascher and Jeanne Jordan, airs as part of PBS’ “Frontline” series at 9 tonight on KCET.

Stephen Heywood was 29 when he found he had the neurodegenerative disease that causes paralysis by killing nerve cells that control movement. After diagnosis, the average life expectancy is two to five years.

Heywood’s reaction: He married, had a child and rebuilt two homes, even as he was slowly losing control of his body. He had the support of family members including wife Wendy.

“What will people say? Will they say, ‘Oh, wasn’t that nice of her to marry that ailing man?’ or ‘Is that fair for him to marry her?’ ” Wendy Heywood says in the film. “We thought of those things and then we said, ‘You know, really it doesn’t matter what anyone thinks.’ ”

Heywood’s brother, Jamie, started a research foundation aimed at speeding up creation of a drug to combat the disease. ALS is not a focus for most major drug companies because it’s an “orphan disease” that affects a relatively small number of people, according to the film.

The foundation’s iconoclastic approach and its struggle for funds is detailed, but its focus is Heywood and those close to him.

Their story also was told in the 2004 book “His Brother’s Keeper: A Story From the Edge of Medicine,” by Jonathan Weiner.

Heywood died last November.