Since she doesn't drive all that much chances are the water pump was not damaged. Flush the system with a cleaner and fresh water then refill with 50-50 water and antifreeze.
If she lives in NYC I suggest selling the car before the first winter gets it loaded up with road salt. For the cost of parking, maintenance, repairs and insurance she can rent a car when she needs it. That, plus the salt will destroy the car in 2 or three years anyway.
2005 4.0 MT dual exhaust GT mufflers GT suspension and wheels