Can a juror be found guilty of failing to disclose to the jury that their brother was suffering from addiction?

failed to disclose the brother's addiction, much less that the reason for the non-disclosure was to avoid excusal (as opposed to embarrassment) or to conceal some bias that could have prejudiced the trial. Cf. United States v. Colombo, 869 F.2d 149, 150-51 (2d Cir. 1989). Nor can such an inference be drawn from the mere report that, upon the start of deliberations, the juror was one of those favoring conviction. Because the jurors had then heard all the evidence, a juror's prompt assessment of that evidence cannot by itself suggest impropriety.