HELP PLEASE!!!!!!!!!!!!!!!!!!!!!!?

i just want to understand one thing, my brother is 15 he EAts junkfood everyday he dooesnt excercise he doesnt wash his face, he touches his face when his hands r dirty, he stays under the sun the whole time and YET he doesn't get acne?! but i take care of myselfffffffffff like ALOTTTT and i still get breakouts?! why is this happening?.. what should i do?..