Glad no one was hurt -- shaken up, for sure. Vehicles, well, they don't last all that long under the best of conditions, so try not to worry about it.
I've had two similar situations -- once when my wife hit a patch of black ice on a long downhill on the Mass Pike. The car (a hatchback) was totalled. Afterwards, we found her glasses underneath the spare tire. The state later billed the insurance company for replacing the guard rail she hit.
Fast forward about 10 years and I was driving home from New Hampshire in a raging blizzard in my rear-wheel drive Mazda 929. I drove extra carefully, but still didn't get 5 miles (out of a 52-mile commute) before doing a 360 and having the car attempt to back itself into the lake alongside the road. This being cheap NH, the guard rails were telephone pole sections connected by wire cable. Luckily, the cable held. The car was sort of drivable (I stayed overnight with a co-worker and got home the next day, after the storm was over), but soon got replaced by a front-driver.
(Now that I recall, that was a pretty darn dangerous commute for me -- I worked up there for four years, and had three major accidents. In addition to the one mentioned above, I fell asleep at the wheel one morning and woke up in time to choose between hitting a guard rail and a stone bridge abutment. I was hell on guard rails during that period. Another time, driving home about 10pm one night the car went BANG as something hit it -- turned out a deer was running across the road, hit my left front fender, took out the rear view mirror, and left some hair behind in the rear door handle. No other sign of the deer, though. And I never saw it at all, just felt the impact!)
Anyway, glad your family is still OK, Munk. Hang in there buddy.
-- Russ