Is a person truly considered a disbeliever if they experience obsessive-compulsive thoughts that make them think God does not exist, even though they do not wish to disbelieve and resist these whispers?

A person afflicted with obsessive thoughts (waswasah) is not held accountable for the words that issue from them, as long as he dislikes them, is averse to them, and is keen to rid himself of them. His dislike of them is a sign of the sincerity of his faith. He must make up the prayers he missed under the influence of these obsessive thoughts.