Rocket launcher in his chest dive for the ammo supplies to the left. Stock up. Throw EMP grenade when he's stunned use rocket launcher again. Then it should be fairly straight forward after that if you avoid his grenades and direct fire and finish him off with combat rifle to the face.

Fire the Rocket launcher at his chest then dive for the ammo supplies to the left. Stock up. Throw an EMP grenade when he's stunned and then use the rocket launcher again. It should be fairly straight forward after that if you avoid his grenades and direct fire. Finish him off with combat rifle fire to the face.