Can't speak to Melichar to complete pestilence - Quest permanently bugged?

[Tiny Tot]

So I did the entire quest for pestilence all the way to taking the prisoner to Rattay to be tried (and likely killed). However, I didn't know that there is apparently a specific way to cure and talk to the prisoner. I didn't try and talk to Melichar to let me into the barn to heal and speak to the bandit. Instead, I knocked out the watchman, placed him into a secluded area, pick pocketed a key from him and entered the barn that way. The game did give me the "you're trespassing" warning but I didn't care because it worked so who cares? Well apparently I'm not the only who is unable to do this according to a search on google. The problem is I haven't found a solution for this.

Every time I go up to Melichar, regardless of the time of day, I always only have the option to pick pocket him which isn't what I want. The quest keeps him as a marker to talk to him in order to complete the quest but I can't. I've even reloaded the save files I have and nothing. I also really don't want to do the entire quest and everything before that (if I loaded an earlier save) so I think this quest is permanently bugged. Can anyone offer suggestions?