I am surprised that you don't have anything "on" your bro so that you can blackmail the sob into submission. When I was your age I had my older brother scared that I would rat him out if he ever did anything to screw me up. My older brother and I had an agreement of sorts and didn't compete for our parents attention anyhow.
That bro of yours sounds like he needs to be taken down and soon. Just be smart and patient and remember to gather solid evidence like pics or recordings. When you are ready for the sob, don't say a word just leave a copy of an incriminating photo about where he can find it and then wait. When he asks you about the photo pretend not to be arsed then mention that you have a collection of them and you will try to be more carefull that they aren't left unsecured, then give him a little wink.