Can not answer the question about how likely she is to make the connection (and I doubt anybody really can as customs can be 5 minutes or an hour in most US gateways).

But do keep in mind that if she misses, not only is she owed the hotel room but EU-261 compensation. So should come out fine compensation wise.

If it is more important to get home, she could ask AA to fly her to ATL and pay for the ground transit home.