Here's my best guess as to what he's singing in the YouTube recording:

BLACK-EYED SUZY
As sung by Roscoe Holcomb

1. Black-eyed Suzy stayin' in the corner,
She a pretty girl, 'pon my honor.

CHORUS: Hey, little black-eyed Suzy,
Hop up, pretty little black-eyed Suzy.

2. Rain come in, the sun come in an' drown me.
Stand back, pretty girl. Don't come around me. CHORUS

3. Ho, little kitty-buss, poor little feller,
Poor little kit-cuss died in the cellar. CHORUS

REPEAT VERSE 2 AND CHORUS.