I have steatosis and hep C. Steatosis is fatty liver disease and can lead to liver problems. Steatosis is also a precursor to type 2 diabetes. It effects the way the body handles insulin. It can be reversed through diet and excercise. My doc has me doing that before I treat for the Hep C. Here is an excellent link to get more info. Good Luck.
http://www.medicinenet.com/fatty_liver/article.htm
Sorry I don't know much about it, most of the people here have hep C (and some hep B). I do know that steatosis is usually associated with obesity and it's a condition where the liver basically storehouses excess fat. If we were all cavemen (and women) living 40,000 years ago, this would be a good thing because food was always scarce or could suddenly become scarce at any time. So the stored liver fat was a hedge against starvation which would allow human beings to survive for a longer period of time in the event food availability suddenly went from plentiful to slim pickens. Unfortunately the flipside of this ability to store fat in our livers doesn't translate too well into modern times where there's an abundance of fat and calorie rich food readily available 24-7 (at least in the west it is).
I would imagine that if your husband were willing to make aggressive lifestyle changes that involved all the usual suspects - primarily diet and exercise, and especially to get his cholesterol down (possibly with the help of statins), then that would go a long way at helping reduce or maybe even resolve the NASH. And as a long term hep C patient, I've learned that the liver can heal itself, it can repair much of the damage that may have been done to it by either disease or poison (usually in the form of alcohol). If the liver is not too far gone (like well into cirrhosis), and the offending agent or condition is removed, it's pretty well accepted and understood that the liver can and will reverse at least some of the damage. And if you had relatively minor damage to start with, it could revert back to completely normal. Not sure if the exact same thing occurs with NASH if the underlying driver behind NASH is eliminated (primarily obesity and high cholesterol), but I can't think of why not.
Also this reminds me of a documentary I saw a while ago called "Supersize Me" (which you can rent at the video rental store). The main character in that movie deliberately exclusively went on a McDonald's fast food diet for a whole month. He had a complete physical prior to starting his diet, and then had regular checkups as he progressed through his "month of McDonalds." He gained weight rapidly and was developing steatosis towards the end of his experience. His liver enzymes were elevated and the fat rich food was basically bringing him to his knees. It's also interesting to make note of a French delicacy called foie gras, which is fattened goose or duck liver pate. It's made by force feeding the animals for a few weeks prior to slaughtering until their livers are enlarged and fattened. The over feeding causes fat to be stored in their livers (just like in people), which gives it a very rich and buttery taste. So strangely enough, foie gras is basically steatosis pate.