One child is being mocked in the team group chat

I would treat this as a football welfare issue even if the messages are being sent from home. If teammates are using a team-related group to repeatedly target one child and that player is withdrawing, the club has a reason to act. “Banter” is not a useful test. Look at the impact, the repetition and whether one player is being singled out. I would save or report the relevant information through the club welfare process rather than asking the child to confront the group themselves. The coach can also reset the team standard clearly: the same respect expected at training applies to team communication online. Do not run your own investigation through the chat or start publicly identifying who is to blame. Support the child, involve the appropriate adults and use the club’s anti-bullying/safeguarding procedures. A team environment does not stop at the touchline when the group chat is part of how the team communicates.