Entity Reference multi value fields, filter on parent
Add a Contextual Filter in your view, use the "Member" field (Entity Reference guess) from your content type "Family".
Then add a relation in Relationship section, using the same field (Member).
Add a Title field and use that relation.
Pass the NID of your family has an Contextual Filter in your preview... you might get all the members of that family.


Notice: in yout Contextual Filter you have to select how will you pass the Contextual Filter (Family's NID in this case). You can add it via URL, etc.