Here is my suggestion. Stop cutting the lawn. If your brother doesn't automatically start doing it, then I would agree with another who said he is a POS. Later if your parents ask you to do it, ask them why he will not. If they say they don't want to ask him, them you tell them how you feel. If they say they asked and he won't, then you should take it up with him. If your man enough to kick his azz, then DO IT! Or at the very least, make it clear that you are capable, and willing, to flatten him if he doesn't straighten up.