The only known sibling of Thomas B. Sanders was Edwin T. Sanders, b. 1806 in Franklin/Wake Co., NC. I strongly suspect that one James R. Sanders, b. c1804 in same county is a sibling, also.
I saw the name Drury Sanders more than once in doing my research, but I didn't keep any notes on him. Try the book "Kinfolks of Franklin Co." if you haven't already looked there.