It's not handled on a case by case basis. The EU designates countries as 'dangerous' and from there on out its member states are required to provide asylum.

This does have the result that ocassionally refugees return back to their country of origin to visit family or even go on vacation. Which is a bit dubious indeed, but such individual actions are not sufficient to revoke refugee status.

Normally yes, if the refugee status was granted on the basis of "persecution by the government or wider society" since one wouldn't normally visit a place you're going to be persecuted.

For refugees of war, it is granted for different reasons.