Ontariotech,
A80 (Atlanta Approach) radar does have weather display capabilities, they can see level one through six weather (preciptation), as does my present facility FWA. The Enroute Radar facility (Atlanta Center) weather display is lousy and not good enough to vector aircraft through weather.
Since I wasn't there I can't say how bad and to what degree the weather was, but if they were holding for Atlanta it had to be pretty bad.
To correct a misnomer, the pilot did not have to declare an emergency, all he had to do was declare a medical emergency and request to be vectored for the approach (hopefully one that would had kept him out of any severe weather). As someone else stated the captain is responsible for the safety of his passengers and aircraft so the go, no go decision is his. No controller is going to willing vector a pilot through severe weather, but we will do everything within our abilities to assist a pilot with a medical emergency or a declared emergency.
Apparently the weather at Nashville was good so the controller sending the pilot to Nashville was a good decision, and one that maybe the pilot should had made earlier, but he has to weigh his decision on safety first, and the convience of his passengers second. I'm sure that he was in contact with his company and who knows they were telling him to wait and hold.
Mike
NATCA FWA