Russell surname in TN, AL, and AR

Hi folks. I'm trying to find information about Dr. Robert Morrow Russell, born 1827 in TN to parents John & Nancy Russell; family moved to Dekalb County, AL in about 1834. He attended medical school in Nashville in 1859 and lived in Saline County, AR in 1860. In 1867 he married Martha Glenn (in Saline County, AR), and they lived in the Hot Springs, AR area until 1874 when they moved to Johnson County, TX.  I'm specifically looking for 3 things: (1) information about what Robert Morrow Russell did during the Civil War; (2) definitive information about who his mother was (lots of conflicting information on Ancestry.com, but best supposition so far is that she was Nancy Lackey, born in South Carolina); and (3) a photo of Robert Morrow Russell (at any age, in any place). I appreciate any help anyone can give me. Many thanks!