So you probably aren’t getting more dialogue with him because Barcus is dead. If I recall correctly, they have a conversation at this point. Since typically it’s Barcus who asks you to rescue Wulbren, the game may not be accounting for the fact that he can be dead in this scenario. I wouldn’t call it a bug so much as the game overlooking a possibility. You may have more problems in the future, on the Wulbren questline, if Barcus isn’t there.
