I t is the responsibility of the local church to exercise church discipline. Finally, you bring him before the church and appeal to him once more to repent. If he does not repent he is put out of the church and is viewed as an unbeliever. Those in the church are responsible to call him to repentance. They are not allowed to have normal relations with him as long as he remains in an unrepentant condition.
Any verifiable sin is grounds for church discipline.
When someone is removed from the church, or excommunicated, he is denying that he wants Jesus Christ to be his Lord. Denial of the Lordship of Christ is a denial that one has saving faith. That is why all those who are put out of the church are viewed as unbelievers.