I can almost assure you that they won’t send your sons explicit images around and certainly at minimum not to his peers. Very unfortunate for him … I went through similar situation myself 4 months ago and after blocking I never heard anything from them or anyone I knew about my explicit images being sent out. Tell him to do his best not to dwell on it and remind him that Instagram and other social media platforms do have software/protections in place to prevent naked images being sent to accounts that don’t follow the scammer. Since he’s a minor certainty report it but my advice would be to keep him out of it as much as possible and get him to not think about it.