It is some times best to read or listen to some other person talking about the same subject:
"Master gave a veiled teaching; he did not reveal all of his thoughts. Those who were interested by this first approach could follow him and become one of his disciples. One could be such a disciple without abandoning one's family or one's work.
Then the Master gave other teachings--deeper, more practical, more direct. He explained the meaning of the parables.
One of the higher steps for the circle of disciples was to repent and to receive John's baptism. It was the close disciples of the Master, the 12 apostles, who were to baptize the students who were entering a deeper level on the path.
Once a candidate had received the baptism, he entered an inner circle of a more restricted and secret School. Inside this circle, the Master transmitted a profound initiatic teaching, as well as certain precise methods. He said that he was working on the future of humanity through the intermediary of his students who had been thus prepared. The students of this secret School included women as well as men, although men were in the majority because of that time period. The discipline was strict, as in the Essene communities"
What we can learn from this Quote is that Jesus teachings to his disiples was Esoteric, so is the Toltec teachings that we know. Furthermore it was not about faith and salvation, it was about exercises, methods teaching etc even discipline is mentioned but not to forget, it was much about Joy and Laughter.
"Master Jesus himself was always careful about the place in which he taught or practiced the works of his Father-Mother with his disciples. Thus, when he was in Jerusalem, he went and taught the crowd in the square of the Gentiles or in certain places in the streets of the city. People knew where they could find him.
With his disciples, he liked to go outside of the city. Thus, he often arranged to meet the members of the inner circle in the garden of the 12 palm trees, which was located close to Bethany. There was a spring there, and the Master had explained at great length that this place was tied to the work which his faithful disciples would have to accomplish in the world in the centuries to come.
He had revealed to all of them the purpose of his mission, the future history of humanity, the different incarnations of his disciples, and the role they would have to play in this history to serve Christ. Once again, he had alluded to the mysterious role of the Apostle John, and he had placed him in parallel with John the Baptist, the prophet Eli and the Essene Brotherhood-Sisterhood."
Therefore the disciples addressed each other with "brother" or "sister".