It either you use Headhunters whole game with Tauren or gruntapult dont switch. It will work far better if your friend goes fiends with statues. If he goes fiends go grunt tauren and healers or the bloodlust casters. You both can use ranged if you want, coz your friend can have ABOMS.
He always has a few statues along with his army. I'm assuming you want him to develop Destroyer form, as an anti-air measure? My Tauren aren't going to do anything versus air. Normally, my favorite setup includes: 2-3 Heroes / A few Grunts(Taurens late-game) / A lot of Headhunters/Berserkers / A group of casters.
Problem is, we either win or lose as a result of our beginning rush.