Why was aunt Helen so important to Charlie

Aunt Helen was Charlie's favorite person during his early years. In the process of recovering from childhood experiences of sexual abuse, Helen struggled with alcohol, drugs, and abusive men in her adult life. She moved in with Charlie's family in an attempt to recover, and she spent a lot of time with Charlie and his siblings when his parents were out of the house. Many of Charlie's best memories from childhood relate to time he spent with Aunt Helen, and Christmastime - which Aunt Helen made memorable - gives the teenage Charlie great sadness: Aunt Helen died while on a trip to buy Charlie, whose birthday falls around Christmas, a birthday present. In high school, Charlie continues to struggle with her death, particularly because he believes that he is at fault. At the end of the novel, it is revealed that Aunt Helen had sexually abused Charlie, but that he concealed this transgression out of love for her and empathy for what she went through as a child.