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

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

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