Defending someone in a felony case is not a do-it-yourself project you can handle with some advice you got from the Internet over the weekend! Unless you are a licensed attorney, there is nothing you can do to help his case; in fact, your efforts could backfire and wind up hurting him.
Your brother needs an experienced criminal defense attorney. If you can't afford to hire a lawyer for him, he should ask the judge to appoint the Public Defender at his first court appearance.
Please understand that this is a general discussion of legal principles by a California lawyer and does not create an attorney/client relationship. It's impossible to give detailed, accurate advice based on a few sentences on a website (and you shouldn't provide too much specific information about your legal matter on a public forum like Avvo, anyway). You should always seek advice from an attorney licensed in your jurisdiction who can give you an informed opinion after reviewing all of the relevant information.
I agree with Attorney Marshall's answer and would add be VERY, VERY careful talking to him in person or on the phone as most, if not all, conversations are recorded and I've seen many a good case go bad from these recordings.
Good luck with your situation.
In order to reduce his felony to a misdemeanor, if that's possible, or to fight against the felony charges you need to hire a lawyer for your son.
Call me at (213) 479-5322 maybe I can help you.
Edward J. Blum