Partner's HUUUUGE Blunder

[hooptown]

JV Tournament finals. Under 0:10 to play. Home team is fouled on a shot and goes to the line down by one. First free throw is made, but partner waves it off emphatically. Shooter's foot was on the line. Crowd goes bananas! This is partner's 2nd or 3rd goofy call in the half, but is the only call in the game that will be remembered. Next FT is missed, visiting team wins by three.

Postgame partner says "I hated making that call, and such a nice kid too".
The home coach sends a nasty email to our convenor blaming "the refs".

My question: What is the best course of action in this situation as it unfolds. Obviously standing at lead, mouth agape does not reverse partner's call (whoops). Is bearhugging partner and demanding he invent a reason to overrule himself the right move?

More generally... besides OOB and backcourt what calls are reversible if partner is new or "goofy"? Other overrules I have seen
basket interference -> T for hanging on rim
common foul -> intentional (excessive contact) foul