People that get restarted generally aren't brain dead. Generally they're heart dead (heart not beating) but the brain keeps clicking for a while after that (until the lack of fresh oxygen going to the brain because of the heart does enough damage that the brain stops). Brain dead is irreversible, heart dead isn't.
This author is only talking about people who's EEGs have flatlined. No electrical activity taking place in the brain at all. Granted, the equipment has not become necrotic or you're correct, we couldn't get them back. So this is the experimental universe we are limited to.