'Gleason' is an extraordinary portrait of parenthood (R)

The first thing Steve Gleason did after learning he was succumbing to Lou Gehrig’s disease was turn on his camera. The former NFL safety was diagnosed with ALS in 2011, around the same time that he and his wife, Michel, discovered they were having a baby, and he began producing a series of video diaries expressing his fears and doubts and dispensing nuggets of fatherly wisdom to a son he would likely never speak to in person.

Those videos, so raw and immediate and nakedly emotional, make up a good portion of the documentary “Gleason,” which stares as unflinchingly and candidly at the effects of terminal illness as few films I’ve seen.

Born and raised in Spokane, Gleason played football for Gonzaga Prep and later played as a linebacker for Washington State University. After college, he was signed by the New Orleans Saints, and although he was smaller in stature than many of his teammates, he was such a lithe and go-for-broke player that his intensity was likened to that of a kamikaze pilot.

It seems especially cruel, then, that someone so well known for his physicality would be afflicted with an illness that brings about such swift deterioration. Steve’s speech becomes slurred and his mobility becomes limited. Soon he can’t move or speak at all, communicating exclusively via eye movement recognition software on a computer attached to his electric wheelchair.

Director J. Clay Tweel has unparalleled access to surprisingly intimate footage, both tender and painful, as Steve’s symptoms intensify and Michel’s role as caretaker becomes a full-time job. ALS is an ugly, rapacious disease, and the film is bracingly frank in its depiction of Gleason at his lowest. Even during humiliating and agonizing medical procedures and moments when it appears that Steve and Michel’s marriage might fold under the weight of his illness, Tweel’s camera doesn’t shy away.

“Gleason” also turns out to be a powerful examination of father-son relationships, especially in its depiction of the oft-antagonistic dynamic between Steve and his dad, Mike, an evangelical Christian concerned that his son’s faith is wavering. In one of the film’s most agonizing passages, Mike takes Steve to a faith-healing church service shortly after the diagnosis. Steve attempts to stand up and run down the aisle as the congregation chants encouraging platitudes, but his legs keep buckling beneath him.

But “Gleason” is not a two-hour slog, despite its grueling subject matter. There are instances of levity and joy and unexpected humor between the howls of despair and pain, moments of clarity where the Gleasons realize that they can weather the storm together. It’s uplifting in ways that don’t feel trite or unearned.

With: Steve Gleason, Michel Gleason, Scott Fujita.

Writer-director: J. Clay Tweel.

An Open Road Films release. Running time: 110 minutes. Vulgar language. In Miami-Dade: Sunset Place, Aventura, South Beach; in Palm Beach: Shadowood.