I've killed morokei, He's hell since he attacks by throwing ice at you which immediatly halves your health and drastically slows you, his health is immense and he also starts with 3 dragon allies, though I found a glitch. kill a dragon, go inside of it's ribcage, find new hiding spot that you can shoot through. I killed morokei with that. you dont need to hesitate or stop shooting, he wont find you. and he rarely moves.