Capt. Timothy Walker

I'm still at the "brick wall" for the parents of Hillary Walker born in Maryland 1782. I have connected with 2 descendants of Hillary's who have done the yDNA. My uncle tested for me. Three of Hillary's sons' descendants have tested and 2 matched but the 3rd didn't. I found an application for entry into the Sons of the American Revolution and someone had stated that his greatgrandfather (I can't remember how many greats) Hillery Walker was a son of Capt. Timothy Walker. The problem is Capt. Timothy Walker's will does not name Hillary. The application to the Society was from some time in the 1920's. Does anyone know what kind of proof they needed to submit, if any? I would like to hear from any descendants of Capt. Timothy Walker.