From #'s link. Seems to be a a play titled "Old Soldier: a One Act Play by Rob Davis"

(There is a pause as gets up and walks to the cabinet. He looks furtively around to see if is watching, sees that she is nowhere in sight, and delves into the cabinet drawers, fetching out a bottle of whisky and three glasses. He returns with them, pours a measure into each glass, and passes one to and before taking one himself. They clink glasses without comment, raise their glasses to each other and drink a toast)

(As they drink, he starts to sing, softly at first, then full and confidently, to the tune of Here's To The Next Man To Die [aka The Eton Boating Song])

As the old Serjeant-Major lay dying
And there on his death-bed he lay,
His comrades all gathered around him
To hear of the last words he'd say.

Take the trigger-guard out of my kidneys,
take the magazine out of my brain;
take the barrel from out of my backbone
and assemble my rifle again.