I believe that the Marhaba lounge has pay-in access, though it's not too interesting. Plus there are hotels in each terminal which, though not cheap, are quite nice.

The Dubai airport offers good amenities to just walk around. Though of course 8 hours is a long time. Is she there during the day? If she has a U.S. passport, I would recommend that she leave the airport and take a tour of the city. Or go to Souq al Bahar and enjoy the atmosphere.