lets see, dad has an '05 Freestlye(basically the Wagon version of the Five Hundred, which is the Ford model that matches up to your son's car.) and Mom has an '09 Taurus (Same body, Different Drivetrain - Duratec 3.5l & Ford 6F trans, vs. the Duratec 3.0 & either a ZF CVT, or Asin 6Speed auto)
they have basically stayed with the factory tires on both.
Freestlye came with the Conti's Mentioned above(215/65-17), never really complained of much issue when we've had snow, though he has replaced them 2 @ a time roughly every 30k mi(but i've read a lot where the AWD system on that model(w/ the CVT)eats tires.)
Taurus came with Pirelli P6's(225/55-18), and she just replaced them(approx 50k mi)with the P6 Plus. never a snowy complaint.
I Put a set of Pirelli P4's on my Neon Last fall, after reading a glowing review of them on discount tire's site. guy in MI had 'em on his neon, and they worked so well in the MI snows, that he never felt the need to switch to his winter tires.
all of the above tires were From the Local Ford Dealer...
well...I got the P4's for the Neon From Tire Rack, but had the Ford Dealer do the install.