Hello Mr Vasu ,
I have understood your concern as to why you should be having NAFLD inspite of being a teetotaler.I would say that your body habitus and also genetic predisposition play an important role in getting NAFLD.
Kindly get your BMI tested and probably you need to keep a watch on that ..also get a lipid profile
done and consult your physician ..
Daily brisk walking for 30 min , 5 days a week would help ...
You can continue the medications as advised by your physician..
Hope I was of help.