When David B. says: “Sometimes I wanted to kill my brother. I wanted it to be that he didn’t exist and that life would be simple”, it jars because he speaks in the ho-hum monotone of a man faced with an onerous trip to the supermarket. He is neat, quiet, utterly unassuming.

But Epileptic, the astonishing, autobiographical graphic novel with which he has made his name, is anything but restrained. This is its first English translation: originally published in France to great acclaim in six volumes, titled L’Ascension du Haut-Mal, it tells the powerful story of what happened to David B.’s family after his elder brother Jean-Christophe was found to have epilepsy, aged 11.

It’s very moving — and in its comic-book portrayal of the mechanics of strained family life, very funny. Marie-Claire and Jean, Jean-Christophe’s parents, endure the insensitivity of doctors and turn to alternative therapies. The family travel from their suburban home to crazy retreats and drive hundreds of miles to buy macrobiotic food. The oddest experience, David B. (the “B” stands for Beauchard) remembers, was being woken by one guru at 4am to bang drums and chant. “He was mad. I couldn’t understand why my parents were into people like that. But there was always the idea of curing my brother. They tried all those things for a reason.”

No treatment worked or helped. Day to day Jean- Christophe could be docile — so much so, David would torture and tease him — or volcanic, in which case the family would batten down the hatches and wait for the tempest to abate. “I was 5 years old when I first saw one of his attacks,” Beauchard remembers. “He was playing on the back of a motorcycle. He began to fall. I didn’t understand. I thought he was joking around. It was the first time I caught him.

“Because of his illness he could be violent. I was able to recognise the moment when he had an attack. I saw it on his face, in his eyes” — this is captured piercingly in the novel. “I was a little boy and it was hard to have a normal life. I wanted to play without a brother who falls over and destroys the moment.” Jean-Christophe’s unpredictable behaviour scared the neighbourhood kids so much that David and Florence, his sister, were left isolated, too. That suited David — not so much Florence, who is “very fragile” — and he retreated into himself. “Everything was structured around my brother’s epilepsy. Of course, I feel my parents neglected me. I didn’t say anything, complain, ask anything. I learnt early to do things on my own. I was very independent.”

David started drawing — battle scenes to begin with. “This was the way I saw things with my brother — as a war,” he says. Later he changed his name to David: he was christened Pierre-François, “but I changed it because in some cultures when a baby is born he is given a false name so death cannot claim him. I think I wanted to escape the illness of my brother.”

As a small boy Beauchard was “sometimes very angry, sometimes very frightened, sometimes very saddened” by his brother. Even though sometimes he wanted him dead, “he was so present that it was difficult to imagine being without him”. His most detailed drawings evoke his boyhood fascination with the spirit world. His beloved grandfather — “we were able to understand each other without speaking” — is represented as a beautiful bird.

Mostly though, Beauchard felt trapped. In the book he draws himself encircled by strangulating, suffocating chaos. As soon as he could, he enrolled in art school in Paris, but he felt lonely there. National service was more fun: he had a cushy desk job and a sergeant he used to go to the cinema with. He began to draw for comics and, with a group of other comic writers, founded L’Association, a group of radical French cartoonists. He published the first volume of Epileptic in 1996, more drawn to the challenge of rendering raw autobiography in an unconventional medium than to exorcising demons. He is now bracketed with Art Spiegelman and Marjane Satrapi and has since won a slew of awards.

While Epileptic represents an “escape”, it hasn’t been cathartic. Late in the tale, as a young man with his first serious girlfriend, Beauchard is told he has bifurcated sperm, which on the page looks very funny. However, their battle to have children is anything but and comes to nothing. The relationship fails. Now settled with his longtime girlfriend Ilaria, and living in the Parisian suburbs, he has no desire for children. “My sister has children and I’m happy with that,” he says. Is he worried he could pass something on? “Yes.” But there’s nothing wrong with him? “No, there is nothing wrong, but who knows?” He laughs. “It’s my brother again — they weren’t able to cure him. I never want to see another doctor ever again.”

That isn’t the only un-neat ending. Beauchard’s mother didn’t speak to him for three years because of Epiletic. “She thought it was her story to tell, or that I should tell her story. She claimed I wasn’t present at some of the events I draw — like when my family tried to contact spirits using a ouija board. But I was. We speak now, but it’s still . . . My father is not happy, too, but felt I should be free to write what I want.”

Jean-Christophe, now 47, is in an institution in the South of France. He and Beauchard, 45, see each other twice a year for a day or so at a time. “He gets jealous and thinks my sister and I will take my mother away from him. He’s not able to read the book. He says he doesn’t know how I remember everything so clearly. He can’t remember anything — because of the medicine and all his falls. We are still like strangers.

“I feel he is embarrassed around me. I frighten him — because I work, because I am a normal man, because I have a girlfriend, because I do books. He tried to write books but couldn’t. He speaks slowly. I speak quickly. He feels inferior. I’d like to be able to do something good for him, but I don’t know how. I want to tell him that I love him. Perhaps we could do things in a different way. But he doesn’t want that from me. He wants something from my mother and that’s it.” Jean-Christophe, he says, is “not able to do anything except be ill and be angry”.

He says this plainly, without any tone of superiority or superciliousness. Has he exploited Jean-Christophe’s illness? “I don’t think so. This is also my story. I can think only about me by thinking about him. My mother said I had exploited him, but I cannot tell the story of my family without telling his. If my brother or mother want to produce their versions, so be it.”

Beauchard is working on a book about dreams; their “unique logic” fascinates him. You sense that he will always feel more comfortable in the sphere of dreams — with their interplay of reality and fantasy, and fantastic shapes and consequences — than in waking reality, where his demons still encircle and torment him.

Epileptic by David B. (Cape, £16.99; offer £13.59 plus £2.25 p&p)

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