Question for biblical scholars- The Gospel of John?

This question may require knowledge of texts not included in the Bible. Who was the disciple that Jesus loved? I don't mean Mary Magdalene, though I believe she was a disciple and he loved her, but this refers to a man. At the last supper, Simon Peter asked a question to "the disciple whom Jesus loved, who was reclining next to him." Another reference from the crucifiction says that when he saw his mother and the disciple he loved and said "Dear Woman, this is your son" and to the disciple "Here is your mother." Finally, at the end of John, Jesus alluded that his most loved disciple will live until Jesus returns if Jesus wishes it. So, who was he? I know that Jesus had close family members who were disciples, possibly even brothers. I think that when he put his mother under the protection of his beloved disciple, he was putting her in the care of another of her sons. Does anyone know or can direct me to somewhere I could get info? Thank you.