... if I did kill the Lawyer I basically messed up the quest and can't complete?
If you kill the lawyer, he re-spawns when the map re-sets. That is why we're telling you to stay at an inn. He also doesn't sell anything.
Are you going to the right spot on the map? The North East corner of the map in the little study like area? See
here.
Based on what you saying, the most likely hiccup is a missed step that you think you did. Not saying that's what happening, but in the past when people report the same problem as your reporting, that's what happened with them. So let's give this a try. Note: Don't skip a step because you remember doing it a million times in the past, do them as if you never done them before.
1) Stay at an inn for 12 hours. Again, don't skip this step because you slept in an inn in the past.
2) Go to the hellish lawyer in the hellish cave. See
Hellish Cave map. Screen shot the area, showing his absence, or his dialogue options.
3) After talking to the hellish lawyer, read the Abbot's book. It's in the NE corner of the Abbot. See
Abbot map. Screen shot the dialogue option with the book.
4) After learning the Abbot's secret, talk to St. Admus.
Lastly, if you're using a modified game, or character file, there could be problems stemming from that. I'm not saying you're using a mod, just listing it as a common source of weird problems. (Note: Per forum rules, discussing mods is prohibited.)