It is interesting that many people, when they think of those circumstances that almost compel an adoption of a religious outlook, think of the death bed. They rarely think of how the world of the living might strike one (and I'm not thinking here about arguments from design).

But to turn to your question of whether anyone can ever look death in the face and remain an atheist, David ("le bon David") Hume is a fine example. He used to drive James Boswell mad in his refusal to embrace the Christian faith: "Read Hume till you was sick," one of Boswell's journal entries reads. Boswell even had dreams of Hume confiding in him that he really was a believer. But it was all a dream. When Hume was dying, he used to entertain a veritable procession of clerics eager to witness his conversion. But they all left him disappointed. When Boswell told Samuel Johnson of this, the latter framed a most ingenious explanation (The Life of Johnson, 16 September 1777):

Boswell: I said, I had reason to believe that the thought of annihilation gave Hume no pain.

Johnson: It was not so, Sir. He had a vanity in being thought easy. It is more probable that he should assume an appearance of ease, than that so very improbable a thing should be, as a man not afraid of going (as, in spite of his delusive theory, he cannot be sure but he may go,) into an unknown state, and not being uneasy at leaving all he knew. And you are to consider, that upon his own principle of annihilation he had no motive to speak the truth.

Two observations about this. First, the sly argument Johnson offers in his last sentence is taken up very interestingly elsewhere on this site; see for instance, Question 27 or Question 200. Second, there is a wonderfully ironical echo in Johnson's first argument for why we ought not to take Hume's "appearance of ease" seriously of Hume's own argument for why we ought not to take evidence for miracles seriously.