I have been diagnosed with NASH by the doctors at the National Institute of Health in Bethesda, MD. I am participating in a CLinical Trial there for the treatment of NASH. Has your brother had a biopsy? His prognosis would depend on what they found in the biopsy. Anyway, my papers from the doctors at NIH say that it leads to cirrohsis in 10 to 15 per cent of patients. This is considerered very low by the doctors. I had a biopsy and I have moderate inflamation and moderate fibrosis. The doctors told me my prognosis was good. I'd be glad to give you more information. Post again with more questions or comments.
Check the American Liver Foundations website for information. It is www.liverfoundation.org. Click on Liver Health, then Liver Disease, General. Then click on Fatty Liver. Scroll down and read the paragraph about "Can Fatty Liver lead to other liver diseases?"
Also the website www.gastro.com has some information posted about nonalcoholic steatohepatitis but it is trickier to find it on their website. Here is the complete website address: www.gastro.com/liverpg/nash.htm
Hope this helps.
You might have already seen these....but just in case...
here's a couple of pretty good sites:
http://www.cpmc.org/advanced/liver/patients/topics/fatty_liver.html
http://www.endowsec.com/pated/ecdlv37.htm