I am a neurosurgeon, and am also skeptical. Here are some thoughts after looking at the actual paper in Med Gas Research.
First, after looking at the MRI, I see more evidence of cerebral edema than of infarction. The MRI sequence that would show the actual infarction, DWI is presented, but as a 3d volume(which I have never seen done before with DWI) and does not show the thalami where most of the FLAIR hyperintensity is.
Second, Unlike what the article would have you think, there is not massive cortical infarction. In fact the cortex looks not too bad. The main lesions appear to be bilateral thalamic edema. Note that thalamic dysfunction can present with severe neurological deficits often mimicking massive cortical dysfunction.
Third, measuring volumes in an MRI that is not taken at 1mm slices can be problematic. Thus where the authors talk about volume differences may just be slice variations between scans.
Fourth, I would have expected something this groundbreaking to be in NEJM, JAMA, BMJ, Lancet, Stroke, or Neurology. Medical Gas Research is a very obscure journal.
Fifth, Paul Harch is way outside the medical mainstream. During the Terry Schiavo case in Florida he was one of the people arguing that she was not in a permanent persistent vegetative state. It seems like he pushes hyperbaric oxygen to treat a host of brain disorders such as cerebral palsy, autism, stroke, traumatic brain injury. There is very little actual scientific studies backing up these assertions.
So overall, I am very skeptical about this article. In addition, usually when groundbreaking science is presented by the press, you often have an expert in the field who was not involved with the study, talk about methodology, background, and implications. This article did not do so, making it all the more suspect. I think, ultimately this is another Newsweek poorly researched click bait article.