you have to figure that because of the way she was raised she has no fear of people like Edward or Tracy. She's been right there with them. And Tracy has sort of had to be nice to her, or as nice as Tracy can be, because of wanting to have a closer relationship with Edward.
And Edward has already approved of Isaac and told Isaac to call him Grandpa. Has Edward already unwittingly endorsed Isaac? you think Hill would take it that way?
I think Edward has endorsed Isaac as a saver of Hill's life, not necessarily as a boyfriend! Those are two entirely different circumstances!
