I state up front that I am not an expert, nor do I practice medicine. I just read a lot, and I try to internalize what seems to be common learning uttered and posted by others with arrhythmias who have had treatment.

A CHA2DS2-VSc score of 2 is what tells the physician counselling the patient that they should be on a DOAC. Your dad can always refuse if he is willing to bear the risk of a stroke which is typically close to 6 times higher than a typical patient without arrhythmia. I dunno, if I were his age, otherwise doing okay, not expected to live another three years or so (which might be realistic if untrue), and my fibrillating rate is consistently less than 80, I would be tempted to opt out of a DOAC. But, if I liked living, could reasonably expect to live another 6-8 years (which might be quite reasonable for him), and I was in and out of AF, say twice a week for about an hour or more, I would take the DOAC. But that's just me. If my rate were higher than 110 when in AF, I would definitely take the DOAC....if I knew I was good for another four years or more. On the other hand, if I were generally feeble, not enjoying life a great deal, lonely, sore much of the time, and probably within a year of a natural death.....................I would hold up my hand and say fuggeddaboudit.

That's a long and convoluted way of saying he should inform himself of his risk, and marry that to his will to live and his apparent life expectancy. He should probably be on it, but it brings risks such as when falling and getting a brain bleed. Not taking it might mean bedridden for six months until he dies from despair, but after a catastrophic stroke.