Novelist needs help with cancer question:?

My son had abdominal sarcoma with multiple tumors . . and was pretty much normal for three years . . ate anything he wanted . . had excellent quality of life . . I am uncertain if your character is going to be all that realistic . . the reality of cancer is not at all the way movies and books try to portray it. For the overwhelming majority of patients . . life is pretty normal unless they are in treatment or in the active process of dying.