After some digging, it appears that Doctor David Midkiff was in Co. H, 56th Enrolled Missouri Militia, Mustered in on August 8, 1862 in Cape Girardeau. Mustered out May 15, 1863.
He also served in the 8th Provisonal Enrolled Missouri Militia from May 16, 1863 til Nov 8 1863.
Henry was in the 2nd Artillary for a short period, Mar 30 1864, Cape Girardeau till deserting June 17, 1865
Robert's service exactly matches that of David's in the 56th EMM and 8th PEMM. Robert was a Sargent and David was his Corporal in the 8th PEMM Co. E.
George served with David and Robert in the 56th EMM but did not apparently transfer to the 8th PEMM.