Rear Suspension problems of the 1996 Chevrolet Lumina

In August 2008 I purchased a clean white 1996 chevy Lumina with less than 100,000 miles on the dash. It seemed to be running pretty well at first but I noticed the car had a little skip every now and then in deep curves. Then on November 1, 2008 the front left axle broke a loose from the main port as I was leaving my yard which was strange and uncommon. On November 8, 2008 a licensed mechanic was hired and fixed the broken axle on the front driver side tire. After the repair the car was test driven and seemed to be running as good as new. Later on that night while my son was going through a curve the car loss control and started fishtailing in the middle of the curve. As he was straightening the car back out into his lane something malfunctioned in the rear and sent the car spinning sideways and out of control. The car stopped itself after running in a ditch and smashing it's side into an embankment injuring him and totaling the car. Rear right side wheel came completely off from where traction bar broke.