What is the authenticity of the claim that the prayer of one who drinks alcohol is not accepted for forty days, and should he still perform it, and is he considered to have left the fold of Islam if he drinks it after knowing the Hadith, and how does one confront someone who does not believe in the Hadith about the four times?

Drinking alcohol is one of the major sins and must be avoided, as Allah Almighty says: "O you who have believed, indeed intoxicants, gambling, [sacrificing to] stone altars, and divining arrows are but defilement from the work of Satan, so avoid it that you may be successful."

And according to the Prophet, peace and blessings be upon him: "Whoever drinks alcohol, Allah will not accept his prayer for forty mornings." The meaning of this is that the reward for prayer is not attained, not that the prayer itself is void or invalid. In another hadith (definition): "If he does it a fourth time, Allah will not accept his prayer for forty mornings, and if he repents, Allah will not accept his repentance, and He will make him drink from the river of Al-Khabal." This is meant as an exaggeration in warning and deterrence, otherwise, whoever repents from a sin, Allah accepts his repentance, as Allah Almighty says: "Say, 'O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.'"

Drinking alcohol is a great major sin that necessitates sincere repentance, but it does not nullify the prayer as long as the Muslim does not deem it permissible, and one who drinks alcohol does not exit the fold of Islam.