There has been recent legislation to outlaw forms of synthetic marijuana. This does not mean, however, that the substance you had is an illegal substance. The state attorney will need to have it tested to see if the substance you are accused of possessing is indeed illegal. I would recommend contacting a criminal defense attorney as soon as possible, and stop talking about your case online.
I agree with the answers from my colleagues. It is important that your brother contact a local criminal defense attorney immediately. He needs to request a hearing with the DHSMV within 10 days of his arrest or his driver's license will be suspended.