I'm not related but I was able to find the following information and I hope it helps you some.
William Harrison Nash b. Abt 1857 OR m. 1889 Dora E. Buchanan (b. 10 Nov 1869 TX d. 05 Mar 1950). Dora married 2ndly Samuel E. Peck. Children: 1) Zoa E. Nash (b. 24 Feb 1890 OR d. 18 Feb 1990 Multnomah County, OR) m. Fred Emil Brown (b. 09 May 1884 St. Peter, MN d. 21 Apr 1960 Portland, OR)
2) Jay B. "Brownie" Nash (b. 10 Jul 1891 Marion County, OR d. 05 Jan 1972 Marion County, OR) m. 1st 06 Aug 1929 Vancouver, WA to Anna M. Ingram. 2nd 1943 to Theresa M. Davis (b. Abt 1909) 3rd Grace M. (b. 11 Sep 1912 d. 17 Dec 1980 Marion County, OR). Theresa and Grace may be the same person. I'm not sure.
There is a wedding announcement for a Douglas E. Nash who married Nancy Lou Berry on 10 Mar 1973 and it says his mother was Mrs. Theresa M. Nash. It doesn't list his father which may be because Jay B. Nash died in 1972.
I looked up Douglas E. Nash and as of 2002 his address and phone number was 12270 SW Albert St, Portland, OR 97223 (503) 590-6274. You may want to contact him to verify.