Just going through that first part, a 100 foot freefall down the cliff, probably gave the elder driver a heart attack.
He had very likely been driving up and down those mountain sides for years. All it takes is one mistake or one distraction from looking at the road ahead.
I was on a similar trail in the San Juans and was a passenger in a Jeep. It came a downpour and water was rushing off the mountain, across the road. I got out to check it out, and had we went over at that particular spot, we would be surfing down a huge drop on a waterfall. I refused to do it, and walked across the water rushing across the road. My friend, however, drove across it.