Becky, your suggested offer of your Dad and/or one of your younger brothers most unfortunately won't do any good at all. The line you detailed contains two females between them and Elijah Abernathy and it is an inescapable fact of how Y-DNA is transmitted that dictates that a pure male-only line is required in a Y-DNA surname study.
Alas, your Dad and brothers would do excellently if I were studying the Finch surname but are useless for the Abernathy/Abernethy surname study I am assisting with.
I am pleased to know of the descent, however. Thank you for that and for your interest.