If your power steering pump is run by electrical current in your car then yes a bad or dead battery as well as a faulty alternator could cause loss of power to the electric power steering pump which could cause loss of power steering.
But if your vehicle has a power steering pump that is run directly off the engine itself then the dead battery can't and won't affect the power steering since that kind of power steering is run off a belt that's being driven by the engine when it's running.