Hi Denise: Great story! According to : Black,Copper & Bright , The District of Columbia's Black Civil War Regiment, by C.R. Gibbs
Dennis Weaver is listed as Pvt., Co. D, joined at age 19, occupation , waiter, joined on 6/14/1863 at Mason's Island, Virginia and listed his birthplace as Alexandria, Virginia.
Note: Masons Island has also been called Analostan Island, but is now known as Theodore Roosevelt Island, and is in the Potomac River across from Georgetown and the Kennedy Center in Washington, D.C. The Island was the camp of the 1st. Regt. The First Regiment had a distinguished record in battle at "Wilson's Wharf" (Fort Pocahontas), "Baylor's Farm" and others. Lloyd