I'm just saying the "dirt experience" is not needed for learning to ride on the street!!
"If a motorcycle looses traction, or control, it falls down.: " Not necessarily the case, I remember one time going around a curve hit some shade which caused a hard frost on the pavement, caused my 850 pound full dress Road Glide to lose traction, slid about 8-10 feet semi sideways toward the side of the road at which time moved out of the shade, regained traction and went on my way..
And if you think that that is the case, maybe you need to take a class or two...or more, more is always better!
If they have a large touring bike and cannot pick it up if it falls over they should do one of two things in my estimation... 1, get a bike they can pick up by themselves, or take a class and learn how to do it!! I'm 64, about 5'10" and 190 pounds, and I can for sure pick my 850# bike up by myself.. if I couldn't I'd get a smaller bike!