The busy subgenre of documentaries featuring autistic subjects gets a strong new entry in “Life, Animated,” a captivating portrait of a young man for whom Disney animated movies have provided a powerful lifeline to progress, language and understanding. Interweaving clips from “The Little Mermaid,” “Aladdin,” “Peter Pan” and any number of toon classics whose words and images the 23-year-old Owen Suskind has long committed to memory, this latest film from Roger Ross Williams (“God Loves Uganda”) teems with insights into how children’s fantasy can and can’t bridge a developmental gap, but works on an even more basic, emotional level as a warm testament to a family’s love and resilience. Acquired for North American distribution by the Orchard, this winner of a Sundance directing prize could benefit from its accessible hook and generous sampling of Disney clips to reach a wider-than-usual audience for nonfiction titles of its type.

Cape Cod, Mass.-based writer Ron Suskind, whose bestselling 2014 book about his son’s experiences inspired the film, and his wife, Cornelia, recall their devastation when their son Owen suddenly seemed to vanish emotionally and cognitively at the age of 3: His sleeping became irregular, he had difficulty walking and his speech became garbled and nonsensical. Their fears were concerned by an early diagnosis of pervasive developmental disorder, suggesting that even if Owen recovered the ability to speak, he would effectively be dependent on others for the rest of his life.

But a glimmer of hope emerged during, of all things, a family viewing of Disney’s “The Little Mermaid,” when Owen’s insistence on replaying a particular scene — and his repeated mutterings of what seemed at first like gibberish — led his parents and older brother, Walter (aptly named), to realize that he had memorized some of the movie’s dialogue. In time it would become clear that Owen had, in fact, memorized all the movie’s dialogue, and indeed that of every Disney animated film in existence, having watched and rewatched them endlessly on video. In a second “Eureka!” moment, Ron and Cornelia recall their shock when Owen, after a spell of speechlessness, suddenly articulated a complex insight by drawing a metaphor to “The Jungle Book” and “Peter Pan” — and led them to realize that these beloved cartoon classics might well help enable Owen to learn to speak, read and write.

That the boy did in fact develop these abilities and more is made clear by the many scenes we see of him as an engaging, talkative, high-functioning adult in his early 20s. Williams and his d.p., Tom Bergmann, show Owen confronting many of life’s challenges and milestones head-on: attending group sessions with peers also on the spectrum, moving into his own apartment; starting a relationship with his first girlfriend (a development that lends the film some emotional urgency in its later stages); and traveling with his parents to France to speak about his experiences at a conference. What seems to remain constant is his love for those old movies, a library of which he lovingly maintains (many of them still on VHS) and watches frequently — a passion that he’s shared with many of his classmates, whether he’s holding a group viewing of “The Lion King” or, in a surprise treat, hosting a visit from “Aladdin” voice actors Jonathan Freeman (Jafar) and Gilbert Gottfried (Iago).

But the documentary’s most resonant moments are those in which Owen and his family and friends grapple with the mystery of how these beloved cartoon classics were able to reach some distant, buried side of Owen after all other methods seemed to have failed. As one observer notes, the Disney movies are in many ways ideally suited to viewers with autism: With their emphatic, exaggerated emotions, they may have enabled Owen to process and express his feelings, while their eternal replayability provided the comfort of a fixed script that he could commit to memory. But they also speak to the essential appeal of fairy tales and fantasies, and the way they provide — for people on and off the spectrum — a simple yet essential framework for making sense of the world. (That framework has its limits, too; Walter lends “Life, Animated” one of its more amusing moments when he notes that Disney films don’t exactly allow for an adult understanding of sexuality.)

With editor David Teague adroitly interweaving clips from the movies throughout (Disney approved use of the footage but exercised no editorial control, per press notes), Williams’ film suggests any number of parallels between Owen’s life and the Disney narratives, with their quests for individual freedom and self-fulfillment; the movie touches fleetingly on the respective boy heroes of “Peter Pan” and “Pinocchio,” but mercifully doesn’t belabor the connection. In the one art-imitating-life element that feels perhaps a bit tidily orchestrated, Owen watches “Bambi” shortly after his mom leaves him alone in his new apartment.

Perhaps the most telling insight comes from Owen himself, who from an early age delighted in drawing not Disney heroes and heroines, but those second-banana figures like Iago, Sebastian, Timon, Pumbaa and Jiminy Cricket — all of whom he’s enshrined in his own story, called “The Land of the Lost Sidekicks.” That hand-drawn personal fiction, brought to life by a team of French animators in a nicely rough-hewn complement to the Disney footage, provides an illuminating window into how Owen sees himself and his place in the world. In the end, with its extended interviews with the Suskinds, “Life, Animated” conveys the deeply moving sense that Owen, however fortunate in his choice of obsession, was even more blessed to be born into a family this tirelessly supportive — one that saw the wisdom of never encouraging him to put childish things away.