Was the man mentioned in the Almighty’s saying: "His companion said to him, while he debated with him, 'Have you disbelieved in Him Who created you from dust, then from a drop of semen, then fashioned you as a man?'" an unbeliever? And what was the detailed nature of his disbelief?

The disbelief of this man is the disbelief of doubt. Disbelief is of two types: disbelief that expels its practitioner from the fold of Islam, and it has five categories, among them: disbelief of denial, disbelief of arrogance and refusal despite believing, and disbelief of doubt, which is the disbelief of conjecture, as in the Almighty's saying: "And he entered his garden while he was a wrongdoer to himself. He said, 'I do not think that this will ever perish, and I do not think the Hour will occur. And if I should be returned to my Lord, I will surely find a better return than this.' His companion said to him while he was conversing with him, 'Have you disbelieved in Him who created you from dust, then from a drop of sperm, then fashioned you into a man?'" The disbelief meant here is polytheism, which includes denying the Resurrection.