It is a growing trend for seniors living in 55 and over parks to allow their troubled children or grandchildren to move into their mobile home, which is allowable under civil code Section 798.3(c)(d). They want to help set them on the right path, or give them a place to start over. All too often this kind-hearted gesture ends up getting them evicted from their home.
On occasion it is not the family member that causes the issues but the friends of the family member. Get to know everyone who comes into and out of your home, and if you suspect anything tell them they are not allowed to return. It is your home; you are allowed to regulate the situation. If they return you may consider calling the police and having them removed if they are unwilling to leave. If you do not take control of the situation your neighbors might. Once enough complaints are submitted to the park manager/owners you may start receiving notices. Since your family member is residing in your home you are responsible for their actions and the actions of those they are inviting into the park.