Blackwater Islands Pure intention juxtaposed

The demon didn't like her answers. If anyone could have cured her brother, it was her, and now he was left with no solution. She said they could ease his pain, but—That is not enough. Easing his pain did nothing for their future. Of course, he didn't want Alduin to suffer, but more than anything, he needed his brother at his side, sound of mind. 

How are you so sure there is nothing to be done? He knew the sickness was held in his soul; there was no denying that if anyone had seen the way the ailment painted his actions and emotions. But he was finding her answer difficult to accept.