We seldom encounter this problem anymore. When it does, just have your hunter pull a mob near the prince. This should make the prince back to normal. If your hunter can't last long enough, have your warr tank it. Hope this help.

Because even though you cannot aggro the prince, he will still patrolling around. So when your hunter manage to lure the mobs to the balcony, ask the tanker to tank that mobs and follow where the prince patrol. Follow next to the prince will do the job.