David Baddiel's fourth novel is set in Mt Sinai hospital, New York. Eli Gold, "the world's greatest living writer", is comatose at the end of his ambitious, chaotic, libidinous trample through life. Witnessing his death are his possessive fifth wife, his depressive eldest son and his precocious eight-year-old daughter.

To spice things up, a gun-toting Mormon stalks the narrative. The brother of Eli's fourth wife, who died in a suicide pact that Eli suspiciously survived, he has come to Manhattan intent on shooting the great man. Meanwhile, in England, Eli's 89-year-old first wife is following the story on television while she tries finally to read his debut novel, Solomon's Testament.

Baddiel does some things well. There's a neat subplot involving a detective who tries to frame Eli for his wife's death using evidence lifted from his novels, and the last 100 pages reach a surprising and stylish climax. But the novel is flawed by its own chutzpah. Writing about Philip Roth (on whom Eli is clearly modelled) through a fictional lens is a feat of literary gymnastics that only the most exceptionally limber novelist should attempt. Baddiel isn't quite up to the task.

This novel may have been written by someone best known as a comedian, but it is a proper novel because it deals with big themes such as literature, love and illness. What's more, it is narrated from the point of view of several characters, one of whom is a child. Some bits of it are supposed to be funny; but others, I'm pretty sure, aren't.

In New York, family members congregate around the hospital bed of Eli Gold, an elderly novelist to whom everyone refers as "the world's greatest living writer", and the last "great man". Eli Gold is obviously meant to be a version of Philip Roth (hairy; likes sex; titles such as Solomon's Testament), from which no careful reader will be distracted by the brief apparition of a character called "Philip Roth". It's odd for a novelist to be imagining the death of another novelist who is still alive, or at least to be doing so publicly.

Let's meet some of the characters who are waiting for Roth-Gold to die. Colette is the eight-year-old daughter of Gold and his last wife (here the Roth is adulterated with a tinge of the safely dead Saul Bellow). You can tell she is a literary child-token because she is forced to misunderstand things cutely: "coma" as "comma"; "latter" as "latte". Colette is also our wide-eyed witness to the arch walk-on parts of the aforementioned Philip Roth ("Uncle Philip") and Bill Clinton ("Bill Clinton").

Violet is Gold's first wife, long abandoned and now living in a nursing home, which furnishes the opportunity for an entirely gratuitous mention of Auschwitz. That's enough about her.

Harvey is Gold's son from another marriage, in his mid-40s and the vehicle for the book's laddish comedy: about fancying younger women, hotels, urination, confectionery, masturbation, etc. The stuff about iPhones could not have been performed as part of a standup routine in the early 1990s, but everything else could, and sounds like it: there is the signature profane adjective ("one last throw of this shit dice"), and even a threadbare reference to the habits of "Japanese salarymen".

In keeping with the big themes, the novel also tries hard to lend Harvey some authentic suffering: not only episodes of "depression" but also "OCD" (glibly so labelled), which may or may not be the "anxiety disorder" from which he is elsewhere said to be suffering, and must make for an uncomfortable combination with his "sexual psychosis", though this last might be meant as some kind of joke. No help can be expected from therapists, whom the novel portrays as money-grubbing idiots. Oh, and did I mention that Harvey also has a son with Asperger's? It's really serious.

Excuse me, I nearly forgot  making his way to the hospital, too, is a Mormon man who "has never been out of Utah" but is now bent on murderous revenge, because his sister killed herself in a suicide pact with Gold, which the latter messily survived. The novel punishes the Mormon for what it presents as his cartoonish beliefs by turning him into a transvestite.

Caricature can sometimes be justified by a cruel brilliance of style. It isn't here. In the midst of a passage from Harvey's point of view, the perspective changes abruptly so as to deliver what presumably aims to be a writerly flourish: "If he had looked closely, which he does not, the businessman might have noticed that Harvey's smile is not pure, that it contains within it a lingering frond of bitterness." There is certainly something weird going on with Harvey's mouth. Elsewhere, he is pictured thus: "A sentimental smile sat on his face like a meniscus of untroubled mercury." The reader's hope that, at this point, Harvey will open his mouth and succumb to rapid mercury poisoning is, unfortunately, forlorn.

Daringly, the novel even provides a few brief extracts from the novels of the great writer Eli Gold. "But every morning, he awoke with a palate so dry it felt like he'd been sleeping open-mouthed on the dead soil of the Great Plains at the height of the Dust Bowl." And so, it turns out, "the world's greatest living writer" has spent his career solemnly trying to ape the elaborate comic similes of Blackadder. It probably is time for him to go after all.