If you’d told me that in the same summer as The Fault in Our Stars I would see an even more emotionally taxing film I would not have believed you. If you’d told me that film would be about Glen Campbell, I would have told you to stop drinking and called you a cab.

But probability aside, there I was, at a screening of Glen Campbell: I’ll Be Me, alternating between belly laughs and the urge to sob. You may not know Campbell by name, but you definitely know one of his most famous songs, “Rhinestone Cowboy,” as a frequent show-stopper at any karaoke night worth attending. And you’ll know more, making a mental iTunes wish list as the film goes on.

I’ll Be Me is the story of Campbell’s farewell tour, which was announced not long after his diagnosis of Alzheimer’s. Despite the fact that he was already having noticeable memory problems he couldn’t not do a final tour: the man lives to perform, is very funny, and is an incredible musician. His family, friends, and longtime road and studio crews all had to work together to make the tour happen. Three of his kids—Ashley, Shannon, and Cal—played in the band with him, helping him through the rough spots while his wife, Kim, remained in close orbit, keeping track of the family and managing Glen’s care.

It was Kim who got the film made, through force of will and the conviction shared by her husband to educate people about a frequently misunderstood disease. Kim initially made her pitch to longtime filmmakers James Keach and Trevor Albert, who flatly refused because no one wants to make or see an “Alzheimer’s movie.” But Kim’s persistence wore them down. 1,400 hours of film and three years later, the film that begins celebrating a remarkable career and an interesting, lively human becomes a document of an increasingly unfamiliar person and his family’s struggle to support him through it. The fading memory is there, but so are a host of other unpredictable complications: loss of motor control, paranoia, agitation, and violent outbursts, as well as the intense emotional toll that being caregivers takes on the family.

I had my doubts walking into the film. I expected it to come across at least partially as a vanity piece with a dash of edutainment and nostalgia to broaden the audience. I was wrong—the film is a vitally important lesson about what Alzheimer’s actually is and the impending health care crisis it will cause. 50% of people who live to age 85 will have Alzheimer’s or another kind of severe dementia. 85 is not as old as it used to be, and half of those people will need around-the-clock professional care in dedicated facilities for at least part of their lives. And someone needs to pay for all of that.

The Baby Boom generation (people born between 1946 and 1964) accounts for roughly 25% of the US population right now. They’re between 50 and 68 this year. With no cure and an incomplete understanding of the disease, this expensive deadline looms with the additional sobering fact that most Americans will have at least one parent with Alzheimer’s. And yet most people think it’s just a thing where you lose your memory when you get old. That’s one of the most visible, early signs, but the eventuality is degrading neurological function until your brain can no longer communicate properly, causing incapacitating cognitive and emotional changes, loss of control of your body and its automatic functions until your organs begin to shut down. It’s a long, harrowing road.

Brutal? Yes.

Truth? Yes.

That brutal reality easily explains the laundry list of musical icons, major political figures and leading medical professionals who make sincere and passionate appearances in the film driving those points home. The film manages to shrink down all of the global issues and the disease’s staggering inevitability to a single family’s experience in a way that is legitimately surprising and moving. It’s the opposite of a vanity piece—concerns about boundaries and maintaining a person’s dignity are addressed throughout the film, both for Glen and for what is normally regarded as a very private, painful experience for a family. It’s a real accomplishment of generosity and respect on the part of a number of people to do something like that. Since they have so much other footage of Glen and his family, discussions about creating other educational and professional training materials are underway. It’s a rare film with a mission that manages to continue working toward that mission for years after a theatrical release.

It’s also rare for a poor, rural boy to become a musical legend, which is what started all of this to begin with. His doctors credit the tour and his constant performing for temporarily slowing the progress of the disease. Music is so deeply rooted in Campbell that it seems indestructible even as other parts of his life crumble. It makes the story of his farewell tour compelling, even if you still aren’t sure who I’m talking about. The musical performances are so great that the audience in my theater broke into applause after several of them.

I’ll Be Me feels like two films: one is a musical biography and the other a story about a family dealing with the reality of incurable disease, inextricably tied together by a lifetime of music. Ultimately, that’s the right way to tell a story about Alzheimer’s. It’s a disease that enters preexisting lives, not a litany of dry statistics about a theoretical state of being. To see it enter the lives of the Campbell family is a singular experience.

– Lisa Olson