In John 1:42 it says Peter is John's son. Is this talking about John the Baptist's son? Also, which of the disciples were Jesus' brothers?
John 1:42 And he brought him to Jesus. Now when Jesus looked at him, He said, "You are Simon the son of Jonah. You shall be called Cephas" (which is translated, A Stone).
Simon Peter was the son of a man called Jonah, not John.
Using Strong’s Concordance: Jonas <2495> Ἰωνᾶς Ionas of Hebrew origin 03124 יוֹנָה; Jonah or Jonas = "dove"
Jesus had four brothers
Matthew 13:55 Is this not the carpenter’s son? Is not His mother called Mary? And His brothers James, Joses, Simon, and Judas?
During his ministry his brothers didn’t believe in him.
John 7:5 For even His brothers did not believe in Him.
None of his brothers became disciples until after his resurrection. Then two of his brothers, James and Judas, became leaders in the Church.
Galatians 1:19 But other of the apostles saw I none, save James the Lord’s brother.
This was not James the apostle, the brother of John, for Herod had killed him.
Acts 12:2 And he (Herod) killed James the brother of John with the sword.
Judas (Jude), who describes himself as the brother of James wrote the epistle of Jude <2455> Ἰούδας Ioudas – Judas.
Jude 1:1 Jude, the servant of Jesus Christ, and brother of James, to them that are sanctified by God the Father, and preserved in Jesus Christ, and called.
I hope you find this helpful.