I think it's a bit much saying ''It seems a cure is impossible'' after just trying to get rid of it with the help of a few characters under lvl 5 and a rogue mind flayer xD
A cure through removing it is impossible, because:
A) the brain damage
B) the damage exceeding what can be healed.
This is why I said "unless any of the information is false". It shrivelling and dying in your brain is -- by real world logic -- not safe, either, which is another problem. Perhaps the "real" problem, if you will. You'd need some divine intervention to "medical achievement never mastered before" scale of macguffin to remove it outright.
