Often, failing to appear in court, if you are served with a subpoena or something equivalent, is contempt of court, and you can be arrested and fined, and in some cases you can be held in jail until you agree to "purge the contempt" by testifying.  It's not a good idea, and it probably won't help your brother anyway.Any reputable lawyer will advise you to appear as directed, take the stand, and answer the questions honestly.  If the truthful answer is, "I don't know," then that's what you say, and the same is true for "I don't remember" and "I'm not sure."If you need more detailed advice, based on facts that you haven't included here, please see a lawyer -- someone independent of your brother's defense counsel.  One place to find an attorney is our website, http://attorneypages.com