How to help my son? Listener question

Hi Clare, hope it's OK to message you here. I have a problem I'd like you to discuss on your podcast if that's appropriate.  It's about my 13 year old son who's " friends" have over a number of weeks , dropped him. They don't reply to his messages and don't invite him to join them any more . I have many scenarios in my head for why this has happened and I realise none of them are real..pure fabrication. I suppose my question is, how can I help my son deal with this rejection, my heart is breaking for him . Thanks x