Oh, Rose—this is one dame you want to keep away from kitchen knives and small children. On one hand, Rose is fiercely defensive of her most vulnerable child. "He's not a dummy. He's normal. He'll be just like everyone else" (72), Rose screams at Charlie's father. But Rose's forceful, bordering-on-abusive treatment of Charlie shows how little equipped she is to care for a child. In trying to make Charlie "normal," she refuses to accept him for how he is.
When Charlie visits Rose at her house, it's clear her mental state has deteriorated—she seems to accept her long-lost son in one moment, but in the next she's rushing at him like a crazed bull. It's totally weird, but Rose's rejection of Charlie has a lot to do with her belief that he's a pervert who'll hurt Norma. It's totally unfounded, but it allows Rose to reject her son without coping with major guilt.