The Congress president told them that charges had been framed against the accused in court and justice would be done soon, he said.
The brother said Sonia spent almost an hour with the family and for the maximum time, she was with the girl's mother, who broke down several times.
The family discussed about punishment to the sixth accused, who had been declared juvenile, and to frame a law to reduce the age of being juvenile.
He said Sonia intently listened to them and assured that she would see at her own level what could be done within the framework of the law.
She assured the family, saying they should not worry about anything and she considered them as her family. She said she was personally watching every activity related to the case, he said.
The brother said the Sonia Gandhi expressed grief at not being able to save the girl despite all efforts.
He said it was the fourth time Sonia had visited the family. Earlier, she went twice to the hospital and also met them at the airport when the body was flown back from Singapore, he said.