Personally, I'm still betting that the cleric "removes curse" just as/before the door breaks down or is knocked open.
On the other hand, we know from the oracle that Belkar has less than a year to live. However, as 1) we do not know what part of the year the comic is currently in (spring, summer, etc), and 2) we do not know when the new year begins (winter solstice, summer solstice, and spring equinox are all contenders from history), we do not know how soon Belkar will die. It could be he has almost a whole year before taking the express to the afterlife. Or it could end in just a few (in-comic) weeks.
However, I fully expect him to recover fully before then. Also, note that the oracle did not mention whether or not Belkar would be raised. It could be amusing if Belkar dies just before Roy is resurrected - and then a mistake is made and Belkar is returned due to a clerical error.