Well it sounds like your son plans to follow in the family business, lol. But since you know the source of his reasoning then just use that back on him. Say something like that might work with grandpa but it won't work with me. Might also want to speak with grandpa and get him to set limits for who is in control. Bigger issue is that your son needs to learn that the real world doesn't work that way either and he won't be able to negotiate his way out of assignment deadlines, school rules, etc. Better now than once his grades suffer. Some things are just not negotiable and how we treat our friends is one of them. Maybe start with one particular behaviour like being mean to the other kids and refuse to negotiate so he goes to punishment each time. On other issues try to give him control in the sense of choices - peas or beans, red shirt or blue shirt.