That said, in my son's particular case with this particular friend: when they are playing, the friend pushes my son's buttons to the point of my son having breakdowns. When this happens, the friend will offer my son a chance to do the same thing to him that he did to my son, a form of retaliation to make it even. This is how they often settle a dispute on their own. They try to make it fair. If my son is too upset to want to play anymore, this friend will start to injure himself in a goofy way, like bonking himself in the head. It's like the friend is retaliating on himself. It makes my son laugh and they are best buddies again.
Have a great day!