rikki, good for you that you are trying to find someone to help; not everyone who wants to help, though, will actually have the experience and skill…..hopefully you will find a good match.
Just one point, it sounds like your brother is in a somewhat angry phase—it may be that if he can get a job to support himself and move into an independent living arrangement, the hostility will soften and it will be possible to communicate again. I know it’s painful, but while he is living in your home he may just need space, but try to avoid giving him negative messages. Also I sense your desire to maintain privacy when it comes to your school life. I hear and understand this, but it may be a relief to you if you can find one trustworthy friend to confide in, someone who will respect your privacy and not be judgemental.