Maybe something like: Good luck!
Answer:
The concept of blessing someone (asking deity to care for the person) is outside of the atheist thought process. By definition an atheist does not see there being any deities with special powers to interfere in human life. Asking deity to do something is unsupportable.
If you mean "Do you say 'God Bless!' when a atheist sneezes?" the answer is "Who cares." It would be more appropriate to offer a Kleenex or ask if he has a cold or allergy. But saying something that gives the impression that you think diseases are caused by angry deities or that he might have coughed out his soul are traditional.I Say God Bless you if god were to exist+++Nowadays it's usually just "Bless you!" irrespective of any religious belief.
Better to say Bless You
"Gesundheit" is another way to say "bless you" after someone sneezes. It is a German word that means "good health."
You just say bless you.
Bless is the formal way, bæbæ is colloquial
god bless
If someone sneezes, and you want to say bless you in french, you should say salut.
The way you said it is fine, though many countries don't say "God bless" quite that freely. You might say "Many thanks for your hard work and effort," which will mean the same.
god bless you
In Telugu, "God bless" can be translated as "భగవాన్ ఆశీర్వాదం ఇచ్చాడు" (Bhagavān āśīrvādaṁ icchāḍu).
God bless you and your sister
"Rabb tuhanu chardikala vich rakhe."