Indeed, IF Twain did say "I refused to attend his funeral but
sent a very nice letter saying I approved of it," William Marcy
"Boss" Tweed (1823-1878) would be a likely antecedent. But
documenting that Twain in fact did say/pen those words -- much
less identifying the "target" -- may still be impossible. Of
course those words are very like Twain, and perhaps someone
overheard and remembered. But as for citing a source probably
the best we can ever do is "attributed to."

This brings to mind many such "quotes" that may never have been
quoted, or at least refuse documentation, such as for example
that attributed to Oscar Wilde: "Some cause happiness wherever
they go; others whenever they go." Truer words never spoken, and
very Wilde-like -- but just try to document that one. (Of course
Twain belongs to the former "some" who at times in spite of
himself caused "happiness wherever" he went.)

May his memory be a blessing.
And may we DOCUMENT EVERY quotation.

(Edd Rowell) senior editor
Mercer University Press

P.S. I welcome your corrections. Be gentle, for I am an aged,
fragile, but cranky editor.