What to do with an overtly disobedient child?

my brother is 13, he is the most disobedient kid I've ever met. He refuses to do anything, is really disrespectful, just punched my mom because she asked him to do some housework. All he does all day is eat sleep, and watch TV. He's also very overweight, u have to ask him to do something 10x before he actually gives it thought, and then he probably wnt do it anyway. My mom wants to send him to a military academy for the summer, any suggestions?