He won't need to worry about the rotor beingfrozen on if he's just doing a pad swap, instead of a full brake job with turned or replaced rotors.
When they're rusted in place, my weapon of choice at work is a large plastic-headed deadblow hammer. Just hit it hard on opposing sides working it back and forth. If you install one lugnut back on a few turns loose, you can really swing hard and you know the rotor won't fly off and crash to the floor.
If you'rereplacing rotors and the old ones are frozen, just verify the parts store gave you the right rotors, and knock them off with a plain old steel sledge.
2014 Sterling Gray GT Premium with silver stripes / MT-82 / Brembo / Recaro
Steeda Sports | Koni Yellows | BMR Panhard and LCA Brackets
MGW shifter | Borla S-types