Im in the same type of situation with my little brother too, im 16 years, 5'5, 131 pounds (I used to be 169) and my little brother is 9 years, 4'7, 133 pounds. My mom lets him eat all he wants while my dad gets mad when he eats too much. I think the only solution would be to remove all junk food from the house, but my mom will always keep buying junk food and sodas and she says it would be mean and cruel if we force my brother to stop eating. Im not even sure what to do my self...