In order to appreciate the degree to which Gleason is an emotionally devastating film, one must know about Amytrophic lateral sclerosis (ALS), the incurable terminal disease suffered by former NFL football player Steve Gleason. Once diagnosed, the body begins to slowly fail over a series of months or years as neurons that control muscles die off. By the time it reaches the lungs, an ALS sufferer can no longer breathe on their own, usually resulting in eventual death. It’s a tragic, incurable disease that, in most cases, comes on suddenly with no cause.

Upon his ALS diagnosis at the age of 34, Gleason began documenting his life with the assistance of filmmaker Sean Pamphilon (the director credited in the film, Clay Tweel, came later in the project). It was important for Gleason to document everything after learning of his wife Michel’s pregnancy: he was uncertain how long he’d live to witness the birth of his child’s life.

The film intersperses video diaries the professional athlete made for his son with footage of the Gleason household, chronicling the many challenges and lifestyle changes the family makes to accommodate Gleason’s worsening condition. It starts with a changing gait and slurred speech, eventually leading to crutches, then a wheelchair, and then at some point Gleason loses the ability to talk.

What shines through in much of this footage is Gleason’s go-getter, positive outlook on life that explains his athletic successes — he was credited for breathing life back into the New Orleans Saints after the devastation of Hurricane Katrina — as well as his ability to continue living life to the fullest while he still can. We hear from family and friends about Gleason’s ambitious, hard-working nature, his compulsion to take life risks and, from the footage of his earlier days, it’s apparent the man leads a happy, fulfilling life.

The film doesn’t sufficiently question the contradictions in this well-known hero’s journey as much as it could have, though what saves it from becoming its own cheerleader is the inclusion of Gleason’s ALS effect on others. The film doesn’t hold back from showing the scary, denigrating, and often depressing side of terminal illness — from the exhaustion faced by Michel in taking care of both Gleason and their baby son Rivers, to a harrowing episode in which Gleason is incapable of bowel movements, with the camera present as a nurse sticks her arm up his butt to help him out, to an awkward, quiet scene in which Gleason confronts Michel about a recent lack of attention and care in the final days of footage. This is a brutally honest look at ALS at every stage of the way, and thus becomes a fairly illuminating and heart-wrenching story.

There appears to be little narcissism at play in the family’s life, even despite the constant hurrahs for their charitable organization Team Gleason and Gleason’s budding friendship with Pearl Jam. Michel once remarks on hearing “Congratulations” after a particularly successful drive for the charity, a concept Michel no longer understands. Congratulations on what? she asks rhetorically.

But there is one thing the doc completely fails to acknowledge: The tremendous impact of wealth on Gleason’s journey. By the time Gleason’s lungs begin to fail, he decides to go through with invasive, expensive surgery that an intertitle explains as the stopping point for 95 per cent of ALS sufferers. And it leaves it at that, never exploring the degree to which wealth assists the athlete’s accomplishments post-diagnosis.

And so the film is simultaneously a down-to-earth, relatable watch about a disease that affects everyone the same way, and a very unique experience of an ALS sufferer’s journey greatly aided by privilege. Considering Gleason’s down-to-earth and honest nature, it’s a surprise the filmmakers never thought to ask him about it.