This is an "army" version of the song from around the early 1900's.
I seem to remember seeing it referenced somewhere as being of German origin around the time of a plague(?) and was sung during the early morning as the body collectors went about their tasks.
Funnily enough the simple school tune "Oh My Little Augustine" fits the words ideally.

All the little angels rise up, rise up,
All the little angels rise up high.

How do they rise up, rise up, rise up?
How do they rise up, rise up high?

They rise heads up, heads up, heads up,
They rise heads up, heads up high.

All the little angels rise up, rise up,
All the little angels rise up high.

How do they rise up, rise up, rise up?
How do they rise up, rise up high?

They rise knees up, knees up, knees up,
They rise knees up, knees up high.

All the little angels rise up, rise up,
All the little angels rise up high.

How do they rise up, rise up, rise up?
How do they rise up, rise up high?

They rise arse up, arse up, arse up,
They rise arse up, arseup high.

See how they rise up, rise up, rise up,
See how they rise up, rise up high.

All the little angels ascend up to Heaven
All the little angels ascend up on high
Which end up? Ascend up
Which end up? Ascend up
All the little angels ascend up on high.