The will of Christina Forney Abernathy's Father is dated 24 Jul 1804 and every single one of his children and most of their spouses are mentioned.
Several critical documents about various members of this surname can be found under the documents tab of my website: http://bellsouthpwp.net/n/s/nss8660/dna/dna.htmlhttp://bellsouthpwp.net/n/s/nss8660/dna/dna.html and include the wills of your David (1795), his Father-in-law (1808), and Jacob Forney Sr's (1804) as well as pension applications and other items of interest.
By the by, it is the opinion of certain researchers (myself included) that the James Abernathy who married Elizabeth Cox was a possible 1st cousin of the 3rd Robert, perhaps even even a brother. Y-DNA of a direct male descendant of James' brother Turner confirms a _very_ close relatedness with others whose paper trails all go back to the first Robert Abernethy of Charles City County, VA.
Alas, we are still unable to document the Father of that first Robert Abernethy and prove where in Scotland he came from.
But we do know more than we once did. See messages #2985,#3009 this forum for some more information.