On January 12, 1875, he married Harriet Patterson Smith in the District of Columbia. They were the parents of four children: Elizabeth C., Joseph F., Robert C. and Mary F. Barnes. He is most likely the Joseph Dean Barnes who was a member of the Virginia Military Institute Class of 1865.

The Evening Star Monday, May 15, 1882
Washington News and Gossip
Dr. Joseph Deane Barnes, Acting Assistant Surgeon United States Army, died Saturday afternoon at his residence, No. 2136 Pennsylvania Avenue of dropsy of the heart. He was the son of General Joseph K. Barnes, Surgeon General of the Army (findagrave.com)