Here are two pieces from the Richmond Daily Dispatch, ca 1862 which show two men who died at Castle Thunder and subsequently buried in Oakwood.
This could indicate Keene may be buried there, Oakwood being a tad closer to Castle Thunder than Hollywood.
The Daily Dispatch: September 24, 1862.
Death in Castle Thunder.
--A soldier, named E. L. Johnson, died in this prison yesterday of mumps. His company and regiment are unknown. Johnson was taken up in Lynchburg on the 8th of September, by the Provost Marshal of that city, Lieut. Turner, and sent to Richmond as a supposed deserter. His remains were interred yesterday in Oakwood Cemetery.
The Daily Dispatch: September 10, 1862.
Death of a soldier.
--John J. Rowman, a member of Company D, 12th Virginia regiment, Col. Weisiger, died in the hospital of Castle Thunder on Monday last, and was buried yesterday at Oakwood Cemetery.