Dust in the wind
This idiom or expression means:
Dead.
Gone.
Helpless.
Meaningless.
We are here on earth but for a moment.
We’ve come from dust, and we’ll return to dust.
Q. Have you heard from Martin lately?
A. My ex husband? Oh, he’s dust in the wind. Forget about him!
History:
This is a line from a very famous song written by the great Kerry Livgren when he was with the band Kansas. It has philosophical and religious significance, but has also been used to convey less philosophical meanings such as suggested in the example above.