It can be a power steering pump. That would be heard while idling and turning the wheel. Can be the alternator making noise, possible diode going bad. Or could be what happened to me which was a idler pulley. Idler pulley sounds like a squeak at first but the bearings seize and then it begins a whine. Which later on becomes a very loud high pitched whine. If i were her id tell her to spray some wd40 on the idler pulley bolt area where the bearing is. If it goes away that's the culprit. Can be water pump but pump would make a grinding noise more or less.
1996 Mustang GT, 17x9 front and 17x10.5 cobra r replica rims, 255/40/17 front 285/40/17 rear at the moment,
o/r x-pipe flow master 40 series dump downs, cai/ram intake, 75mm c&l throttle body and plenum, pi heads and intake swap, msd wires, stock gears, untuned at the moment, no dyno numbers for now.