Well, he hardly seems to be a boy (aged 25)!

There is no one on the Broadfoot list serving in an AL unit named David C. Moore (there are two in GA units, one in a TN unit, and one in a VA unit). There are two David Moore's in AL units (1st, 26th Infantry, and Livingston's Cavalry). There are also two D. C. Moore's (12th Infantry, and Camp of Instruction at Talladega), and even one D. Moore (6th Infantry) from AL units. None of these is listed as a Drummer or Musician.

Also checked variant spellings and found nothing.

Someone with access to the Mobile papers for June 1896 might check the obits for clues...