What is the guidance regarding a man who has adopted the methodology of declaring people disbelievers (takfir) to the extent that he has abandoned congregational prayer and has been lax regarding the inviolable rights?

Question:
May Allah reward you, Honorable Shaykh. This questioner says: One of our young brothers, may Allah guide him, has adopted the methodology of declaring people disbelievers (takfir) to the extent that he has abandoned congregational prayer and has been lax regarding the inviolable rights. He has been advised about this and about his speech regarding the scholars, but he has not taken heed. What is obligatory for us to do with him? What is the course of action with him?

Answer:
This is a punishment, and may Allah protect us from it. This is a punishment for what he did to the scholars and his injustice toward them. He was punished with this calamity, which is that he declared the Muslims disbelievers, isolated himself from them, and abandoned prayer in the mosques because he considers them disbelievers.
So this is a great calamity, and thus evil increases in a person, because it is from Satan. Satan is the one who made declaring people disbelievers (takfir) seem attractive to him and increased it upon him until he declared the Muslims who pray in the mosques, call to prayer, and establish the prayer to be disbelievers. So this is a punishment, but we do not despair that Allah will guide him and return him to the right path. It is incumbent upon you to call him to Allah and advise him, perhaps Allah will guide him. Unless he has been afflicted in his mind; perhaps he has been afflicted in his mind, and this is something not of his own choice, but rather because he has been afflicted in his mind and his intellect has been disturbed. This is a different matter. Yes.