Rikki, I hope you remember that none of us have any professional experience in dealing with OTD teens. So this is just our thoughts on the situation, but please don’t make any serious decisions about dealing with this based on our opinions.
I will have you and your brother in mind when I daven, though, and that’s a lot more practical than than trying to advise you based on personal experience with OTD siblings(which I happen to have…). Cuz one thing is for sure-no two situations are alike.
Hang in there and talk to Hashem (and friends, of course)when things get hard…
Good Luck and Good Shabbos!