The guys friend wouldn't be able to join at the treasure room, he can join if it's before the Skolas fight, a five second window when the team wipes. Maybe he joined party chat to be mean? That makes more sense. I'm sorry to hear about your brother, but this is why the game has an age restriction, a lot of under age players don't have the life experience to deal with others online. Be happy he didn't give access to his account to some random internet troll