IF Peter were the head of the Church why would Jesus tell Peter that what happens to John is basically none of his business? In Christ's reply He indicates that Peter has no special jurisdiction over John.Then Peter, turning about, seeth the disciple whom Jesus loved following;
which also leaned on his breast at supper, and said, ...
Peter seeing him saith to Jesus,
Lord, and what shall this man do?
Jesus saith unto him,
If I will that he tarry till I come,
what is that to thee?
follow thou me.
John 21:20-22