Is There Any Treatment For Wernicke Encephalopathy?

My brother is in the hospital diagnosed with Wernicke Encepalopathy. He went to hospital because he fell and hit his head. He has dramatically declined in the 12 days he's been there. I find it hard to believe that he could go down so fast, because up until now it has been a long, slow process. He's 72, alcoholic for 30 years, but haven't expected a rapid descent like this. He's very bad, doesn't even recognize my name any more. Is it common for things to take such a rapid decline without some sort of explanation? Thanks