I am the tank. We do interrupt but the thing that gets us the most is his PBAOE knockback. That hurts when he's enraged. As far as I can see there's no way to predict when he will do it unless I am missing something.
I haven't noticed any way to avoid it, but that shouldn't be killing anyone. The healer should have enough time to heal everybody up since he shouldn't get to do a 2nd PBAoE.