A man has appeared in court charged with stabbing a mother to death at Notting Hill carnival.

Shakiel Thibou, 20, was originally charged with the attempted murder of Cher Maximen while she lay in a coma in hospital. That was changed to a charge of murder when she died on 31 August from the “unsurvivable” injuries she had suffered.

The court heard the 32-year-old victim was at Notting Hill carnival’s family day with relatives and friends on Sunday 25 August, when she was stabbed in the groin.

Thibou appeared at the Old Bailey on Monday via video link from HMP Belmarsh. His brothers, Sheldon, 24, and Shaeim, 21, appeared via video link from HMP Wandsworth facing lesser charges.

The prosecutor, Alistair Richardson, told the court a fight broke out close to Maximen and her group, involving the brothers. The mother tried to intervene in the fight and was stabbed in the area of her groin, Richardson said.

She suffered a cardiac arrest and was taken to hospital, where she underwent two major operations. “In summary she was found to have extensive injuries and extensive blood loss,” the prosecutor said. “Those injuries proved to be unsurvivable.”

Shakiel Thibou, of Hammersmith in west London, is also charged with possessing a knife in a public place and violent disorder. Sheldon and Shaeim, also from west London, are charged with violent disorder and assaulting an emergency worker, while the former faces an additional charge of possessing a stun gun.

The three defendants were remanded in custody before a plea and trial-preparation hearing at the same court on 28 November. A provisional trial date was set for 24 February next year.