Who is my brother?

I was once instructed by a dear brother that all of those with “like precious faith” are our brothers. That on its face is true. What this dear saint meant though was church of Christ only. Our further conversations confirmed that clearly.

So, here is my question. Is every member of a church of Christ my brother or sister?  Isn’t there some things one must believe to be considered a true Christian? Or, is the fact that he is a member of a coC congregation enough. That is obviously the view of many.

A man who shows none of the Christian graces and spends his days being critical of other church of Christ men who don’t agree with him about the supremacy of a cappella music and insists that everyone who does not agree with him is lostIs this man my brother?

A preacher denies the bodily resurrection of Jesus saying as some of the cults that the resurrection of Jesus was only “spiritual”. Never mind the passages that record Jesus walking and talking, and eating meals with his friends after he arose. Thomas touched him as did others. Is this man my brother?

A fellow denies the divinity of Jesus, the bodily resurrection, and even pokes fun at Paul for incorrect teaching and brags that the Jehovah’s Witnesses have invited him to speak for them. Is this man my brother?

What are the foundational doctrines one must hold? What are the fundamentals of the Christian faith? Is the kingdom of God broader than “some” Restoration Movement churches? If so, on what grounds?

Is a person who has been “scripturally baptised” yet believes Jesus was a fraud and liar my brother? Is there an answer to these questions? Where do we draw the line of brotherhood?