Should a judge disclose a relationship to all parties?

I cannot give you a response specifically tailored to your brother's case because there are too many unknown facts, circumstances, etc.   However, I can provide you with some general information.  First, a personal relationship between a judge and a defense attorney that pertains to the judge's election campaign, does not, necessarily require the judge to recuse him/herself or the defense attorney to move to withdraw as counsel.  To use such an issue to try to get a new trial, based on newly discovered evidence, I believe it would be necessary to determine if there was something about the judge's/defense counsel's relationship that affected the case and that, BUT FOR THAT RELATIONSHIP, probably (from a legal viewpoint -- not a personal, subjective viewpoint) would have resulted in an acquittal.  If a relationship contributed or led to errors of law or procedure or to ineffective assistance of counsel, the errors and or ineffectiveness of legal representation were issues that needed to be raised within the requisite time period on appeal (within 30 days following final judgement and sentencing) or by motion for post-conviction relief (within two years following final judgement and sentencing -- or two years following the entry of a mandate if the case was appealed).  A person does not need to know the reason for the errors or ineffective assistance of counsel in order to appeal or file for post-conviction relief.  If you were aware, or should have been aware, of the errors and/or ineffective assistance of counsel at the time, then you must raise the issue then (i.e., within the applicable time periods) -- not wait until you discover what you believe was the cause of such errors or ineffective asssitance of counsel.   As I said at the beginning, I do not know the facts of your brother's case.  Consequently, this response does not indicate in any way that I think there were any errors of law or procedure or any ineffective assistance of counsel.  I would have no way to assess that from your question.