Is it permissible to perform the funeral prayer for someone who was born a Muslim and was known to be a communist, in the following cases: if he denied the existence of God; or if he denied Islam and the prophethood of our master Muhammad (peace be upon him) while believing in God; or if he believed in communism as an economic system while believing in God, His Messenger, and Islam?

Whoever denies the existence of Allah Almighty, or doubts it, or denies the prophethood of Muhammad, peace be upon him, or doubts it, is a disbeliever. And whoever denies the economic legislation in Islam and believes in socialist legislation is a disbeliever. Therefore, it is not permissible to offer the funeral prayer for one whose state is such, because Allah the Almighty says: (And never (O Muhammad) pray (funerally) for any of them who dies, nor stand by his grave. Certainly, they disbelieved in Allah and His Messenger, and died while they were Fasiqun (rebellious, disobedient to Allah and His Messenger)). (At-Tawbah: 84)