The article just says that someone reportedly interviewed a trio in India who claimed to have escaped from Siberia. It doesn't mean that any part of their claim is true, as Rawicz's fabrication shows. The article says "So the possibility remains that someone - if not Rawicz - achieved this extraordinary feat." (My bold) And of course no one actually did, or could, make the journey as described. No one is actually going to see Yeti's. No one is going to walk for more than a week with no water. The latter part is a key element in the story.
Personally, I think a "non-fiction" book that is a lie is automatically a bad book. It was fraud for him to profit from his book in that way. The title of the book is The Long Walk: The True Story of a Trek to Freedom The truth matters.
There are plenty of good books about true adventures out there. And there are undoubtedly many epic stories similar to Rawicz's that will never be told.