This is a very interesting question to think about in relation to this novel, as it is clear that Anne gains little from her family. Note how she is described as being "nobody" to her father or sister:
... her word had no weight; her convenience was always to give way; - she was only Anne.
The way that Anne is treated by both her sisters and her father throughout the novel is shocking in the way that it completely reinforces her inferiority as far as her family are concerned. Yet it is through friendship that this balance is righted, for, we are told, that Lady Russell has completely different ideas about her:
To Lady Russell, indeed, she was a most dear and highly valued god-daughter, favourite and friend. Lady Russell loved them all; but it was only in Anne that she could fancy the mother to revive again.
Therefore the novel suggests, in Anne's case at least, that friendship is of more importance to characters than family.