> until cured

I wrote something before which didn't consider that you're modelling this as an illness. AIUI Breivik isn't mad. There's nothing wrong with him that we could cure, he's a Nazi, he genuinely believes that it's appropriate and even necessary for him to kill children that he thinks are genetically inferior.

He will die in prison not because we couldn't cure him, but because the rest of society are not Nazis and do not think we should identify some people as genetically inferior and kill them. Whether that is because it can't work (which it can't) or because its morally abhorrent doesn't matter.