If you're REALLY having trouble, try getting Aveline 3 points in cunning on level up, maintain Heroic Aura(from either your own mage's level up or Bethany's) on and make sure she's always got everything on her through usage of taunt and keep her under Shield DEfense effects. SInce there's no friendly fire you can AoE to your heart's content with either Bethany or Carver. Make sure to stick to the hurlocks with whoever's not named Aveline, preferably making good use of the fact they're flocking around her to optimize AoEs. Otherwise, focus on keeping auto attacks centered on a single target. If things look sub-optimal, pause, take a deep breath and use a health potion on whoever is in need. Remember, if there's a single hurlock on anyone but Aveline, move such character closer to her and use her Taunt.
To anyone having trouble, this fight is a nice introduction to the concept of aggro management and boss/mobs aggro balancing. Feel free to experiment, you can have Carver or even yourself tank, if not a mage. What I listed is a pretty much sure fire way to pull through, but there's room for trials. Spamming pummel on the ogre is also a good idea, since they have surprisingly low resistances in Normal, apparently. And remember, Warriors are frontal AoE. If using CArver or being yourself a warrior, try and position yourself accordingly to make the most out of each slow swing. You can be missing out on tripling your DPS by going one-on-one.
Good luck mate ^^