In answer to your question; yes, you can fight your citation without a lawyer. But, the better question is "should you"? In answer to this question, I would say, "no." Realistically, you are never in a good position to go it alone in situations like this. How do you plan to prove in court that there was a mechanical failure? And do you know how to get that proof to the jury--and past the opposing attorneys inevitable objections? As attorneys it is our job (and our privilege) to do this for you....
The real question appears to be, can you safely answer NO to a question that asks if you have ever been arrested or cited for any violation other than a minor traffic violation (or similar language)? If this is the case, I would error on the side of full disclosure.
The sad fact is that identity theft can cost far more than having new credit cards or a new driver license--as you are finding out. Taking a pro-active stance now and getting an attorney will help to address the DUI. Seriously consider getting the charge expunged as was mentioned by counsel above. It is not fair, but again being pro-active can help minimize the negative impact on the rest of your life.
If your brother has been convicted, he has the right to appeal, within certain time limits and success would be based on appealable issues preserved during trial. If he has just been charged, he needs an attorney now! He can take advantage of free-consultations--you will be limited in what can be discussed with you personally.
It is the state that determines who and when to prosecute. Unfortunately, you do not get to make that decision, regardless of how you feel personally about it. That is the harsh reality. What you need to focus on is what the state is charging you with and how you are going to deal with it. Many criminal defense attorneys on this site, including myself, offer no-cost consultations, so you can determine the best course of action to take. Please, take advantage of this opportunity.
I would say at this point you need to come clean with your PO and the sooner the better--don't wait until you hand the cup to the technician. You need to be able to establish trust with your PO and saying "oopsie!," when you get caught is probably not going to get that started on the right foot. Come clean, and start off new o. The right foot. And stay clean. It will go better on you now and into your future.
The way you ask the question, it indicates that you have personal knowledge of your boss stealing client funds? Investigators are ultimately trying to determine where to place blame. They are not looking to befriend you, share a cup of coffee and shoot the breeze. In the worst case scenario, they are trying to get you to freely volunteer information that could implicate you in the theft. Best thing to do is to say nothing, and get an attorney, if you have any question as to whether they might...
Very simply get a good criminal defense attorney. If you are just a suspect your attorney may be able to keep you out of the soup. If you are already charged, your attorney may be able to keep it from having harsh consequences rain down on you. You can find just the attorney you are looking for on this site.
In general, you can't be convicted without "a" trial, but you can be convicted without you being "at" the trial. If you were convicted in your absence, and the court had an error (like sending you an incorrect court date), you can have an attorney address this for you and potentially have the conviction set aside and a new court date issued.