CEV translate like this, " A friend is a always a friend, and relatives are born to share our troubles." As I see meant, true friend will share and confide to each others. Notice we have family problems? We share our problems and how to deal with those problems. Now, as you said as friend as of world, like friend of the world is enemy of God, it doesn't mean can't be friend, it mean don't be like them. Like this you have a friend who is drinking, you wish he or she stop, but our job is set a good example and true, don't fall into their influence toward you. But don't look down on them. We share our problem, that is a true friend and should be confide, not to leak to share others about the person problem, that's the biggest damage, and that's dishonor God.