Particularly in the case of Ovinrbaane from the 4th Kingmaker module. The group barbarian has the sword and failed the ego save, so the sword is dominant. He's eventually going to fail the will save for the modified memory, at which point he'll likely end up killing the party.
Remove Curse specifically does NOT work in this situation. So how should I handle it? With the sword dominant, it's not going to let him discard it (I assume). What can the party do?