If a patient has "sequelae of hypoxic ischemic changes" in their brain like in this case, that means a significant amount of their brain cells have died. The surviving brain cells may or may not be able to take over some of the function of the dead ones, but I'm not aware of any current or future technology that can significantly improve the chances of a positive outcome here.

Then again, I agree with you on principle: if such a patient is brought into the ER, the Hippocratic Oath compels doctors to do everything they can to save them. And since ECMO is widely available (thanks Covid, I guess), they can really do a lot, even if the patient's heart is stopped for extended periods of time. If, like in this case, the patient's heart starts beating again, there's "only" the recovery of brain function to worry about. But there are also patients whose brain is working, but their heart doesn't anymore, so they only live as long as they're connected to the ECMO machine (until they hopefully eventually can get a heart transplant), which presents a whole new set of ethical questions...