Jesus’ mother, Mary, was cared for by John. When John’s brother, James, was executed by Herod, this must have sent a chill through the early Christian community.
I speculate that when James the brother of John was executed by Herod, this was an alarm signal to the Apostles. Usually our attention goes right on to Peter who was next. We know that he miraculously escaped, but what I wish to draw our attention to is this:
James was the brother of John.
John was the one to whom Jesus had entrusted the care of his mother, Mary.
Therefore John was a highly esteemed pillar, one whose identity and whereabouts had to be kept under close guard. He was too valuable a witness, as was Mary, to write to, or write about in the early history of the church. Certainly Luke did write about him, along with Peter, in the context of the earliest years. But after chapter 12 of Acts, he, along with Peter, go practically unmentioned until long after the deaths of Paul and Peter.