That's a tough question. Most people are pretty high level when they fight that guy and could solo without trusts pretty quickly. You can try using /yell to ask for help. I am sure someone would be happy to help.

If you really want to do it yourself as RDM 68, I'd have to know what moves are giving you trouble. If you can get Ayame trust, she is pretty useful because she will open skillchains for you. Ayame Unity trust will close them for you. Skillchain and magic burst can go a long way.