Wolff wrote This Boy's Life as a depiction of his mother's, his and his son's lives. He contends that the treatment his mother received from her father--based as it was on vain and false presumptions of superiority next to inferiority and devoid of any notion of human dignity--was the mold that forced her identity, then his, into the shapes they took. He contends too that what his mother experienced still echoes and motivates in the lives of his own children.
Though there is specific detail of the experiences his mother had, and though there are specific details of the ramifications of her psyche upon the molding of his own identity, Wolff doesn't make it deliberately shocking, rather he tells his story by bring out the love that was there nonetheless and in a straightforward manner that doesn't cast blame.
My mother put her arm around my shoulder.
For the rest of the day she kept looking over at me, touching me, brushing back my hair.