Richard Flanagan’s novels have sometimes seemed more interested in themselves than in their readers. His first two, Death of a River Guide and The Sound of One Hand Clapping, clothed their earthy realism in faintly metafictional garb, with circular structures in which their beginnings merged into their endings. His third, Gould’s Book of Fish, was an even tricksier hodgepodge of nested narratives, told by a series of unreliable narrators including an antiques dealer, a forger, and a fish. Although admirable for its formal playfulness, it was as full of itself as a matryoshka doll.

With The Narrow Road to the Deep North, a grim, sentimental novel about the building of the Burma Railway, which won him the Man Booker Prize in 2014, Flanagan abandoned such radical experimentalism. But his new book, which reads like an episode of Neighbours written by Franz Kafka, is in some respects a return to the concerns of his earlier work. Although that might sound like an exciting proposition, the results are decidedly mixed.

There are really two novels here. The first is a carefully observed account of an everyday family tragedy. Siblings Anna, Tommy and Terzo are waiting for their mother Francie to die. Anna is an architect, Tommy a failed artist turned fisherman, Terzo an investment banker. Another brother, Ronnie, killed himself when he was a teenager, and his death haunts the family.

Other unhappinesses stalk them. Tommy’s son Davy is schizophrenic, “tormented by voices”; Anna’s son Gus, an antisocial gamer and drug addict, who spends his days online and steals from his mother to fund his habit.

As the novel opens Francie lies in hospital in Tasmania, condemned to life by machines, medical interventions and the conflicted decisions of her children. Her extended non-dying — an “ongoing delirium of life that was, admittedly, no life” — is set against a backdrop of ecological catastrophe: forest fires, climate change, habitat destruction and animal extinction. These are registered in the novel mainly as a series of hysterical lists — “brexitrump climatecoal”, “Winifuckingbagos more airbnfuckingbs” — intended to convey the sheer plenitude of impending disaster.

Running parallel to this story is a magical realist fantasia about bodily vanishings. First Anna’s fingers go, then other of her appendages. Her friends start losing parts of their bodies, too. These moments of loss are described with dreamlike ambiguity: “a blurring of the knuckle joint, the effect not unlike the photoshopping of problematic faces, hips, thighs, wrinkles and sundry deformities, with some truth or other blurred out of the picture”.

Pretty soon it becomes clear that these losses aspire to the condition of metaphor — perhaps they represent ageing? Global catastrophe? The isolation and loneliness of lives lived online? All of the above? “Everything was vanishing around her as if in some fantastical story”, Flanagan writes, holding our hands a little too firmly, “fish, birds, plants, all were going or on the verge of extinction. And no one noticed, or only for a moment, and life went on until life was no more.” But we are also invited to read the vanishings as straightforwardly literal, which makes it a bit frustrating when characters barely discuss them with each other.

Flanagan’s writing suffers from a similar kind of haziness, with sentences, which on first glance look as though they’re doing precise descriptive work, falling apart under closer scrutiny: “The sun stumbled into each day a guilty party, a violent red ball, indistinct in outline, shuddering through the haze as if hungover, while in the ochry light smoke smothered every street and the smoke filled every room, the smoke sullied every drink and every meal.” A violent indistinctness? That artless repetition of smoke, and “the smoke” both filling and sullying?

Elsewhere “something” is described as “ebbing like a tide”, as if it could ebb like anything else. What emotional truths there are here often come across as trite. “The more she thought about it the more she wondered if maybe that’s what humans can’t do. Live with beauty. That it’s beauty they can’t bear. That what was really vanishing wasn’t all the birds and fish and animals and plants, but love.” This doesn’t even make sense as a cliché.

When novelists invoke the inexplicable they are often forced to play a dualistic game: either eliding literal explanations — asking their readers merely to accept the world they present as fact — or providing a more coherent schema of figurative interpretation. The best do both at once. Gregor Samsa’s transformation in Kafka’s The Metamorphosis is unsettling precisely because it is unsettled: is this really a story about a man transformed into a monstrous insect? Or is it a story about capitalism? Or mental illness? Or anti-Semitism? Like the rabbit-duck illusion, once you have one meaning in mind other interpretations become difficult to see, but they’re always there, hovering behind the figure.

The problem with The Living Sea of Waking Dreams is that it is all vehicle and no tenor. Flanagan’s central metaphor is a flabby one: neither specific enough to do much explanatory work, nor ambiguous enough to sustain much intrigue.

The Living Sea of Waking Dreams, by Richard Flanagan, Chatto & Windus, RRP£16.99, 304 pages

Join our online book group on Facebook at FT Books Café

Listen to our podcast, Culture Call, where FT editors and special guests discuss life and art in the time of coronavirus. Subscribe on Apple, Spotify, or wherever you listen