Families can mean a lot of different things to different people. In Sense and Sensibility, Austen shows us a wide range of family relationships that demonstrate this diversity of meaning. For example, while she shows us many examples of how familial love can help bring someone through a personal crisis, she also reveals how cruel and unfeeling families can be at the same time; we've got everything from sisterly bonding to parents disowning children here. Yet, despite the gamut of different possibilities, family remains the central unit of this story – no matter how much a character's family life sucks, it's still fundamental to that character's existence.
In Sense and Sensibility, Austen's depiction of family life is informed more by economics than by sentiment.
The most important relationships depicted in Sense and Sensibility are those between parents and children; Austen seeks to redefine the commonly accepted conventions of familial obligation and duty by implying that children must break free from the bounds of family in order to find personal happiness.