Lee Roy Parnell and T. Graham Brown are among the artists set to play a benefit concert for Jimmy Nalls, a guitarist and founding member of the 1970s band Sea Level. Nalls, who is battling Parkinson’s Disease, has toured with Brown, B.J. Thomas and Charley McClain. He also has played guitar on albums by Gregg Allman, Bonnie Bramlett and Percy Sledge. Nalls will undergo surgery for the disease Wednesday (Nov. 1) at Vanderbilt University Medical Center. The show will be held at Nashville nightclub Exit/In Nov. 19.