That information is both interesting and helpful to me. I have known for a long time that so-called partisan/guerrilas coordinated with regular Confederate forces in TN, particularly with General Forrest's command. My view is these men were patriots who chose to defend their homes and were no less honorable than the regular soldiers. Napier's Battalion was organized in 1862 when partisan units were encouraged by the Davis administration.
My ggg-grandfather was born in 1820, but his participation would not be unusual for middle aged men from Tennessee. When was your ggg-grandfather born? I have often wondered if partisan soldiers tended to be a little older or younger than those in the regular army. And I think "bushwhacker" was a term used loosely by Union commanders so they could intimidate and murder innocent men. Not saying there were no genuine thugs who robbed and killed civilians (e.g. some of the yankee soldiers).
Joe