Dude, keep it to yourself. Report the player and let it go. You slandering and outing the guy on here is only going to get you in trouble as well. Trust me, my friend did this back in Halo 3 days and got his Xbox Live account permanently banned for Code of Conduct violation. Yes it sucks and I'd be pissed to, but there is nothing anyone can do really. I'll be surprised if Bungie intervenes at all because your brother being younger than 13 is already violating the Destiny Terms of Service. Best of luck for his future games though man.