Paulus died sometime after the Searing. Completing the quests show that he seems to be very close to Melka Blanston, the wife of Gurn Blanston. However, it should be noted that it is debatable whether the body of Paulus in post-Searing is the same Paulus the Abbot. The model used to portray his dead body is different than the one used pre-Searing.
When you get close to Paulus's corpse, you become poisoned. Do not linger, as the poison will not go away until you leave. This poison effect only occurs if the quest Protecting Ascalon is active.