Help - Raven's Cove Quest

[Marry The Night]

I've tried searching the forum, but I've only found help for the Dowsing Rod part.

I'm almost level 31, I've mastered the sword and I'm (somewhat) close to mastering the doll. But still, this quest is kinda hard. Currently I have to defend the Traitor Ghost. If I try to help defeat his enemies, I get knocked out. If I sit back and heal, they all just disappear. Mutineer Ghosts are easy to defeat and all, but it's hard to juggle healing and fighting.. Could someone please give me some pointers, or possibly even help me with this part?