✅Answer: Please pay attention to the following narrations:

📚 Al-Kharaij wa al-Jara'ih, vol. 1, p. 452

[1]: Al-Ma'idah 5- 73.

Ahmad ibn Muhammad said: One of our companions wrote to Imam al-Hasan al-Askari (peace be upon him) and asked about someone who stopped at the Imamate of Imam al-Kazim (peace be upon him) (meaning a Waqifi). The Imam wrote: Do not have mercy on your uncle and disassociate yourself from him, for I disassociate myself from them before God. Therefore, do not befriend them, do not visit their sick, do not attend their funerals, and do not pray over any of them who dies. Anyone who denies an Imam who is from God, or adds an Imam whose Imamate is not from God, is like someone who says: 'God is the third of three' (like the Christians). Indeed, the denier of our last command is like the denier of our first command!

📚 Al-Kafi, vol. 2, p. 399

Muhammad ibn Muslim said: I was sitting on the left side of Imam al-Sadiq (peace be upon him) and Zurarah was on his right. At that moment, Abu Basir entered and asked: 'O Aba Abdillah, what do you say about someone who doubts God?' He said: 'O Aba Muhammad, such a person is a disbeliever!' He said: 'What about someone who doubts the Messenger of God (peace be upon him and his family)?' He said: 'He is a disbeliever!' He said: Then the Imam looked at Zurarah and said: 'Indeed, if he denies, he becomes a disbeliever!'

📚 Al-Kafi, vol. 7, p. 257

Ammar al-Sabati said: I heard Imam al-Sadiq (peace be upon him) saying: Any Muslim who is between two Muslims (his father and mother are Muslim) and then apostatizes from Islam and denies the prophethood of Muhammad (peace be upon him and his family) and belies him, then... on the day of apostasy, his wife is irrevocably divorced from him, and his property is distributed among his heirs, and his wife observes the waiting period of a woman whose husband has died (meaning four months and ten days), and it is upon the Imam to kill him and not ask him to repent!

📚 'Ilal al-Shara'i' 292

Imam al-Sadiq (peace be upon him) said in a narration: Indeed, Allah, the Blessed and Exalted, has not created anything more impure than a dog, and our enemy, the Ahl al-Bayt, is more impure than a dog!

✅Regarding each of the above points, there are multiple narrations. There is no doubt in the disbelief and apostasy of anyone who disbelieves in God, the Prophet, and the Ahl al-Bayt (peace be upon them), becomes faithless, and apostatizes from Islam. Consequently, their ritual impurity is also confirmed.