If there was an agreement for the family member to pay rent, even verbal, you can serve a 3 day notice to pay or quit. Otherwise, you will have to serve a 60 day notice on everyone, assuming as you say, they have all been residing there for over a year.
Yes, these people took possession legally, and they have been there long enough so that they have the same right as any other tenant. Payment of rent, or even an agreement regarding payment of rent, is irrelevant. These are ugly evictions, and they take a lot of courage by the "landlord", but an eviction action is the only legal way to get rid of the freeloaders. Have your family memeber get good legal advice.