Agree with the ladies above. I would also have a 'family meeting' and discuss expectations in the house i.e. keeping room clean etc. Talk about punishments and what he thinks is fair for what situation. He is almost an adult and needs to be treated as such BUT he also needs to understand that he needs to abide by your rules. Communication is the key to this working well.

Good luck. I wish everyone could have such a wonderful sister like you.