Sandy, Midchuck,

The version I know is

McTavish is dead and his brother don't know it
His brother is dead and McTavish don't know it
They're both of them dead and they're in the same bed
And neither one knows that the other is dead

McTavish he suffered from chronic arthritis
His brother he suffered from peritonitis
They both of them died and oh my how we cried
Cause neither one knew that the other had died