Think about which religion you want to be mekarev them to, and whether your actions are consistent with that religion.
So in other words if you have a family of 4. 2 parents and 2 children and the only non jew is the father, it is not consistant to try to mekarav the 3 jewish members.
You dont think chabad deals with this all the time especially in places where there are many non relgious jews many are intermarried?