Amy,
My son Clay (30) had and still has a-fib after surgery back in December. For some people, it goes away permanently after things heal up, but for others it may be a condition that remains. A-fib is not life-threatening, although it does need to be monitored by a cardiologist on a regular basis, as there are some necessary medications, e.g. blood thinners, that stop the pooling blood in the atrium from clotting and potentially causing a stroke.
When you first asked, many of us told you that Alan's symptoms seemed normal, but there is no substitute for being there in person and seeing how he looks and feels. You seem to have really good intuition, and in the future it is probably better to get him checked out if you sense something isn't right.
In my own recovery, I've noted that there is absolutely no substitute for a loving caring spouse!
Hope everything works out well.
--John