Methanol is really, really toxic stuff. As I recall, if you stick your hand in a bucket of methanol for very long, it can kill you dead via skin absorption.
A few decades ago, some docs in Sweden demonstrated that they could reverse decades-long methanol-induced blindness (caused by methanol's nasty metabolites binding to the optic neural system) by infusing (i.e.,via IV) ethanol into those blind patients over long periods. (They kept them pretty drunk for a matter of weeks, as a I recall.)
The mechanism of this cure is different from the one in the case in Vietnam, but it still involves the biochemical competition between methanol and ethanol in the body's metabolism.