Yes, it will be. Talk to his lawyer about this. The judge is going to hear about, and consider regardless of what s/he might say, this latest arrest which demonstrates that your brother is out-of-control and is without regard for the law. Your lawyer might talk to the prosecutor about having the judge consider the new case while punishing the DWI under 12.45 of the Code of Criminal Procedure. This allows the judge to take the new case into consideration in punishing the DWI, and then the public lewdness would be dismissed. (The prosecutor also has to agree to this.) This is just a consideration - if the judge is intellectually honest & truly will not take the new case into consideration (which there really is no reason for him/her not to - then your brother might not want to 12.45 the case because the punishment could be longer, while if punished separately on the lewdness case, it will run concurrently with the DWI.)
Sorry, I know this is confusing. It is easier to explain in person. His lawyer can explain the options to him.
The bottom line answer to your question is that the judge CAN take the new charge into consideration.
Assuming you have provided the totality of your brother's criminal record, then he is looking at a maximum of 1 year in jail on the DWI (and the loss of his privilege to drive a motor vehicle.)
Although I have answered the question to try to help you, you should consult with a lawyer in your area in person on the matter. In addition, my answer does not establish an attorney-client relationship between us.
While I agree for the most part with Ms. Henely's response, I think the more accurate answer is "maybe". Because it is possible that the judge won't know about the new arrest.
If the judge knows about the new case, it will definitely be taken into consideration. A judge should take everything relevant that they know about the case and the person into consideration in deciding the sentence.
Having said that, it is the job of the prosecutor to provide the judge with any negative evidence (including new arrests) relevant to sentencing. The defendant's lawyer is bound by ethics to answer the court candidly and truthfully if questioned about the existence of any new cases, but it is not the defense lawyer's responsibility to bring that information forward.
There are clear indications that your brother may have substance abuse issues. You may wish to consult with a substance abuse counselor to see if his problems can be addressed before he ends up with felony charges, which is most likely the direction he is heading.
Best of luck to you. It sounds like you have your work cut out for you...
Partly it depends on which county or counties his cases are in. In Travis County he should have no trouble getting his sentencing re-set so that his attorney can try to negotiate getting his newest case considered, in a good way - through Sec. 12.45 TPC - in his DWI sentencing. In other counties, it may be harder, but it's worth trying.
This could turn out to work to his advantage, given the facts that already exist.
This answer is intended to be taken as general information and not as specific legal advice. You should always consult a qualified attorney and make him familiar with all the relevant facts in order to get proper legal advice.
He probably should go forward with the sentencing if his DWI is a misdemeanor. This is true because the new arrest is so recent, the prosecutors wouldn't know about it. If you postponed the case, they may find out and pull their offer. The new case sounds like one that could be dismissed if handled properly.