Jesus separated himself from the flesh before he died. He didn’t want to leave his fleshly mother childless so John was given to Mary to comfort her lost of a son.
This is so powerful because Jesus thought about the needs of His mother before she asked.
Now there stood by the cross of Jesus his mother, and his mother’s sister, Mary the wife of Cleophas, and Mary Magdalene.
When Jesus therefore saw his mother, and the disciple standing by, whom he loved, he saith unto his mother, Woman, behold thy son!
Then saith he to the disciple, Behold thy mother! And from that hour that disciple took her unto his own home.