Its tough to know the truth and know that you may never see them again. Pray for your 2 brothers that claim atheism day and night. I would feel secure, depending on the "level" of autism your other brother experiences, on his getting into heaven. I recently watched a video by a young woman, raised in a Jewish household, that gave her life to Jesus and prayed tirelessly for her family to join with her. Her mother and brother are now followers of Jesus as well. Don't give up on them.
Nukes aren't mentioned as such in the Bible, however there is a prophecy that speaks of an ancient city that still exists today becoming a heap of ruins and will no longer be a city. A nuke would accomplish what is foretold.
