1:when te reach the 2nd section of the cave head right pick up the shotgun turn left & fight him
use the shotgun o a grenade when he is covered in bees.

2:when fighting the fear of course te can't see him
when te are in the factory where te get too sokolov(not during vartouis mission)in the room where sokolov was held there is a locker open it & there te will find the terminal goggles use it to see the fear even when he is in camo.

3:after te defeat the pain te walk a river when te are in the end of the river turn left.there will be two soldiers take them out get on the platform...