IMO, he also need to choose the right path of decisiveness. If we should be sellers and goes all in on buying, that is not good, and vice versa.
Of course, it's hard to know in foresight. We still argue about past lanes taken in hindsight.
I've been one of the most optimistic fans on this site, this season, and I'm still nearly certain, selling should be the lane taken.
That being said, if Brez can be a genius and "buy" a younger pitcher with 3+ years of control, at the deadline, I'm all for buying and would even trade top prospects to do that. IMO, that is nearly impossible to do, but maybe Brez can pull it off.
If selling means trading Matthew Lugo, Wikelman, Jordan and Paulino for something decent, then I have no issues with buying. If Brez is done with someone like Wink, I trust his judgment on trading him or the like.
If we trade a top 6 prospect of 2 from #4-20 for a rental, I'd be very concerned about it being a bad choice.