I happened on this info sent to me from another researcher, a decendent of the third son, Thomas, that left Charlottesville, VA and moved to Missouri.
Thomas apparently operated a store in Charlottesville, Virginia. From a book on Early Charlottesville, “The first store room, now occupied by A.D. Cox, grocer, was for several years occupied by Thos. Draffin, who did a large trading business in country produce brought from west of the Blue Ridge by mountain wagons…This thriving trade after a few years came to an end, by the failure of Draffin and Co”.
Of course, this is only a guess. I'd be very interested if your research turns up any add'l information.