2002 Mitsubishi Diamante wipers, windshield & visibility problems

The first time my 5 year old son drove in this car, he vomitted. Everytime he rides in it he becomes nauseous. The car's windshield fogs up and a sickly sweet smell comes out of the vents. The windshield is covered in a permanent haze. We noticed these symptoms but had not given it a second thought since the car was new and had no reason to suspect major problems. The car was recently in the shop for 1 week, when we picked it up we really noticed the sweet smell and alerted the shop.

02 diamante with approx 42, 000 ml - upon starting the car the front window begins fogging up and the entire car then fills with steam that is sweet but overwhelming. It gets so bad it is nearly impossible to see out the front windshield and then the smell overwhelms you within about 5-10 minutes forcing the driver to pull over or drive with the windows down (not easy at 18 deg outside and 2 kids under 5 in the back).