I do not know why you took her off her medicine if it was helping. She has a disorder and needs medical and more personal help than the school can give her. I would tell her you are moving her because the school is not able to provide her the help she needs.

If the public school near you is not very good; is there no private school, no charter school or other school you can afford? It sounds like you are blaming her behavior for the difficulty getting her the help she needs. I don't think she is intentionally being bad and the "now see what you did, you got yourself sent to a crummy school and ruined your brother's life too" feeling I get from your wanting to tell her does not seem like it would help her? She knows she has problems.

Maybe you can find a smaller or home schooling situation that can help?

http://jerseyhomeschool.net/

I would definitely get her individual help, not leave it all to the schools.

http://www.addsolutionsnj.com/