In short, the heavily metaphoric and symbolically driven doc, The Bastard Sings the Sweetest Song, is about Muscle (a Guyanese cockfighter) and his alcoholic mother, Mary, whose tendency to wander off into the streets and panhandle for liquor money routinely places her in harm's way. It's an observational look at breaking the cycle of violence, noting their rocky past through confessional interviews while witnessing their day to day life, where Muscle locks up his mother in a small, dark room to keep her from wandering off, occasionally feeding her shots of vodka to calm her.
His intervention isn't an act of aggression though. While he tries to escape the trappings of his lower class birth, a metaphor driven home by repeating images of roosters confined in small cages, much like the human subjects, he's trying to keep his mother from fulfilling her dream, which is the decidedly less admirable quest to escape this world. She never outright says it, but her indifference to personal health and tendency to discuss being abused and watching nine of her 13 children die helps us draw our own conclusions.
Because the footage itself, unrelated to artistic editing and juxtaposition, is little more than a curiosity about the experience of a morally questionable man and his alcoholic mother in cycles of repetition (she tries to escape; he locks her up; he hosts a cockfight; and repeat), Garland's narrative constructs are necessary. She never forces her hand, or emotion, by injecting anything twee, like a slow motion musical montage, but still ensures that her documentary plays out like an exceedingly realist narrative, mirroring storylines thematically and adding dimension through imagery.
It's because of this careful manipulation of real events into something accessible and universally profound, candidly analyzing the lifelong struggle of escaping a trajectory, that this potentially humdrum documentary works as a layered allegory in its own right. There are structural hiccups that come with the territory of not knowing the outcome while shooting, but Garland's work shows an even hand with an eye for detail. (Murmur)