You can't. You will have to turn yourself in and post an appearance bond. You will then be given a court date where you may be able to reapply for participation in the classes. You should definitely retain an attorney to assist you in this matter.
Act as though you were in church or a synagogue, unless your church calls for loud singing and spontaneous "hallelujiahs". Dress as though you were going to a job interview. (No marijuana leaves on the front of your shirt or anti police slogans). Be respectful and NEVER make a scene, by rolling your eyes, dropping your head into your hands or talking excitedly to your attorney.
Retain an experienced criminal defense attorney in your area to assist you who also understands the immigration consequences involved since certain dispositions will result in you not having a criminal recors yet still effect your immigration status. There are many excellent attorneys here on AVVO and most offer free consultations.
The decision whether to prosecute or not prosecute a case is made by the prosecutor's office. Your brother can certainly contact that office and indicate that he does not want you to be prosecuted, but he is not empowered to "drop" any charges.
You should consult with an experienced personal injury attorney as soon as possible, There are many fine ones here on AVVO. Do you have medical insurance? If so, go get whatever treatment you require. If not, you really need to hire an attorney. Good luck.
Never, ever take a polygraph test administered by law enforcement. Period! Retain counsel to assist you. I have hired private companies to administer polygraph tests for clients and only reveal the results to law enforcement if my client passes our test. If the client fails or if the tests are inconclusive then no one is the wiser. Do not deal with the police alone, particularly if you are a target of an investigation.