Would you be able to cope? That is the unspoken challenge laid down by “The Black Balloon,” a harrowing, unsentimental portrait of a middle-class Australian family whose oldest son has severe autism compounded by attention deficit hyperactivity disorder. Would you find in yourself the seemingly infinite reserves of love and patience possessed by the Mollisons, the movie’s itinerant, highly stressed army family who have just moved to the suburbs of Sydney? Maybe not. The Black Balloon,” directed by Elissa Down, was inspired by her experiences growing up in a household with two autistic brothers, the younger of whom served as the model for Charlie (Luke Ford), a mute who communicates in sign language and heaving, wheezing grunts.
When calm, Charlie is adorably playful and cuddlesome, but when agitated, which is often, he makes noises that assume a feral intensity. At his most intimidating, during uncontrollable tantrums, he becomes a desperate wild animal, flailing and spitting and biting. Mr. Ford, who was seen earlier this year as the hero’s rambunctious son in “The Mummy: Tomb of the Dragon Emperor,” makes Charlie a character whose complexity transcends his disability; you can almost decipher the words he is unable to speak. Ms. Down’s sympathetic alter ego is Charlie’s slightly younger brother, Thomas (Rhys Wakefield), a shy 15-year-old whose love for Charlie is increasingly compromised by his embarrassment. As the new kid at his school, Thomas is something of a fish out of water himself; barely able to swim, he struggles to stay afloat during lifesaving classes.
He is so ashamed of Charlie, who attends a school for the disabled, that when Jackie (Gemma Ward), a sweet, attractive girl his own age, comes calling, he futilely tries to keep him out of sight. “The Black Balloon” offers a wrenching portrait of the Mollison household. The boys’ exhausted mother, Maggie (Toni Collette), only days away from giving birth to a third child, refuses the bed rest ordered by her doctors. When she goes to the hospital to give birth, her husband, Simon (Erik Thomson), a gruff, good-hearted army officer, mistakenly imagines that the house can run smoothly while she is away.
No sooner has she left than Charlie begins wreaking havoc. The scenes of Charlie running amok are agonizing. One afternoon he flees in his underwear and, with Thomas in frantic pursuit, dashes through the neighbourhood and into a strange house to use the bathroom. In a supermarket checkout line he flops onto the floor and begins bellowing when Simon asks him to return some items to the shelves; eventually he has to be dragged out of the store screaming. At one point an angry neighbour summons child services to the Mollisons’ home.
In the most repellent scene, Charlie is discovered in his room smearing his poo on the carpet and over his body. Thomas is expected to clean up the mess. His growing sense of being trapped by his brother’s disability is evoked in moments when he anxiously listens to Charlie’s noises and to the squall of the newborn through the door of his room. The blooming puppy love between Thomas and Jackie lends “The Black Balloon” a welcome strain of tenderness. Mr. Wakefield and Ms. Ward project the innocence of shy, sensitive young people for whom a tentative shared kiss is a very big deal. But Ms. Collette’s Maggie is the film’s prime mover. This wonderful Australian actress, who hasn’t a shred of vanity, virtually disappears into the complicated characters she plays, and Maggie is one of the strongest. With every forceful gesture and glaring look, Ms. Collette portrays Maggie as an indefatigable woman of heart and sinew who, through sheer determination, holds off chaos.