I'll go with the son's interpretation. She is just a nice old lady. Probably has no idea and is just trying to be "fair to all" in her telling. I would say that nice little old ladies probably should not talk to reporters without depositions being taken since what she said, and what the press reports, may have different meanings.
I have no idea about mrs. Knox and her personality, and you're certainly taking the high road giving her the benefit of the doubt. But not all older women are nice ... many are downright vicious.