I do it all the time by myself on insane lol. Get the Torque Bow and Longshot. Try to stay away from him (by going to each side avoiding the light) Shoot him with a torque to get the krill of him, then shoot him as many times in the face with the longshot
as you can, rinse and repeat until he dies.
look, use torque bow hits to the face to drive of locust bats. he only takes damage as they uncover his face. hit him up close with all fours grenades as you hit him in the face with the sniper rifle. it took me 4 minutes. great u tube video shows you how