Most of my information on this family is trapped in a laptop that crashed! I think I can help you, though. William and Thomas are indeed brothers, both sons of David Whorley and Martha "Patsy" Payne.
Marriage Record Nov. 19, 1803; David Whirley & Patsy Paine; John Nichols, surety. (Bedford Co Virgina marriage book, not mentioned in Quaker records) David was the s/o Francis and Patsy Worley [yes, another Martha - Patsy was the common nickname for Martha at the time]. David and Patsy had at least 10 children in Bedford. David died in Bedford about 1823.
Francis Worley married Martha Payne in either Washington Co. or Frederick Co., Maryland. This Martha Payne was the d/o Thomas Payne. Francis and Martha Worley came to Bedford 1778 or 1779 and Francis died 1780 in Bedford leavind 3 or 4 small children; Flayll, David, and Hannah, who may or may not have been Joanna, so there were 2 definite sons, and 1, possibly 2 daughters. [Hope that is not too confusing.] I have been trying for several years, without success, to determine who Francis' father was. Several possibilities, no proof! Hope this is some help to you. Let me know if you'd like more - maybe you'll energize me to take the laptop in and see if I can at least get my family tree off of it!