I see this combination of expressed preference and actions (would prefer not to live with brain damage, but then actually choose to live with brain damage) as a failure of imagination and incorrect far-mode statements, NOT as an indication that the prior statement true, but was thwarted by some outside force.

Future-me instances have massively more information about what they're experiencing in the future than present-me has now. It's ludicrous for present-me to try to constrain future-me's decisions, and even more so to try to identify situations where present-me's wishes will be honored but future-me's decisions won't.

You can prevent adverse revival by cremation or burial (in which case you also prevent felicitous revival). If an evil regime wants you, any contract language is useless. If an individual-respecting regime considers your revival, future you would prefer to be revived and asked rather than being held to a past-you document that cannot predict the details of the current the situation very well.