I would think think the NA beer would just contain carbs. The carbs would just be converted to glucose via normal digestion. Excess glucose (high glucose spikes in the blood) can be converted to fructose but that would be associated with blood glucose spikes like a diabetic has. So my thinking, from the fructose, alcohol and liver standpoint, the non alcoholic beer would not be a problem in that respect. 

Alcohol and fructose are processed exclusively by the liver and are the main culprits of fatty liver. The dose makes the poison. A little is probably not particularly good for the liver, but it can handle and process it effectively. In excess amounts over time (chronic over consumption) is where the problem comes in.