Mohamed Merah murdered seven people, including three Jewish children, in a series of scooter-borne attacks in the Toulouse area in March. He was killed resisting arrest after a 36-hour police siege of his flat on March 22.
In the book, a newspaper interview and television documentary, Abdelghani Merah blames his parents for the way they raised their five children. He accuses his father, a convicted drug-dealer, of repeated child-beating and his mother of neglect.
But he blames Mohamed's attraction to the teachings of extremist and anti-Semitic Islam mostly on his own sister, Souad, and brother, Abdelkader.
For a television documentary to promote the book broadcast on Monday, Abdelghani helped to film his sister secretly as she proclaimed her "pride" in Mohamed and declared her hatred of Jews.
The second Merah brother, Abdelkader, 30, has been under arrest since March and is under investigation for complicity in the murders.
Souad Merah, 32, has been questioned but has not been linked to the attacks.
In the documentary on the M6 TV channel, Souad was seen and heard saying: "I am proud of my brother. He fought until the end ..."
The young woman, who has links with the fundamentalist Salafist Islamic movement, says at one point that she suspects she is being recorded. But she goes on: "Mohamed had the courage to act. I am proud, proud, proud - Jews and all those who massacre Muslims ... I detest them."
She is now the subject of a criminal investigation, judicial sources say.
The probe will establish whether she breached French law that prevents individuals from publicly defending terrorist acts.
In his book, Abdelghani Merah describes Abdelkader, or "Kader", as a "tumour".
He recalls that in 2003 his brother stabbed him seven times after he refused to give up a girlfriend with Jewish origins.
At the time, he said, he warned police in Toulouse that if there was ever a terrorist attack in the city they "only need to go after Kader".
In his book, Merah paints a miserable picture of his own and especially of Mohamed's childhood.
He says his father, also called Mohamed Merah, "beat me so much that I could no longer feel the blows. He also struck Abdelkader a great deal. Mohamed less so, because he was too small."
The future killer was 4 years old when his father abandoned the family and became a drug dealer, for which he was convicted and jailed.
His mother, Zoulikha, then in her 30s, "went out all the time, had all kinds of scrapes and left Mohamed alone all day in front of the TV".
At the age of 8, Mohamed was placed in care.
"My mother said to him, 'Stay there during the week and I'll come for you at weekends.' But she would never come and it drove him mad with unhappiness."
Merah also recalls visiting his mother's house for a wake for Mohamed.
There were whoops of joy, he said. People were congratulating his mother and saying, "Be proud. Your son brought France to its knees."
"I screamed: 'My brother is not a hero. He is a common assassin."'
-Independent
