What does Tis well mean?

I believe those we're last Word of George Washington, before he died? Maybe, he pronounced "it's" uncorrect due to his illness, cannot be sure though..

Therefore "It's well"

Until well into the 19th century, " 'tis " was considered a quite appropriate and common contraction for "it's" or, more formally, "it is". (Of course, at that time, "ain't" was also considered an appropriate contraction for a number of phrases - (is not, am not, are not)) Therefore, "Tis well" is, simply, "It is well". It is believed, in essence, to be, simply, an acceptance of the inevitable.