My friend Kristi Smith (Alaska Gal on allvegaspoker.com and vegaspokernow.com) just posted the above series of tweets; read from the bottom up.
This sort of thing is precisely why I tend to be a hard-ass about people talking about the hand in progress. Sure, a lot of the time it doesn't really affect anything, but once in a while it does. And once it does, it's too late to do anything about it. The people who engage in it tend to have no sense whatsoever of what can be said without affecting the action, so cannot be trusted to have appropriate levels of discretion. The only cure is prevention. So I speak up about it when it has apparently done no harm in an attempt to prevent it from happening again in a moment when it will hurt me or someone else.
I see now that I've done 31 previous posts with this general subject as a label, so you can maybe tell that it's something of a crusade for me. Perhaps the best of these posts is here, where I list 16 common kinds of talking during a hand that break the rule because they might change how another player makes a decision. At least twice I have lost a pot because of somebody butting into a hand inappropriately; see here and here.
In Kristi's case, the dealer should have spoken up immediately when the friend started talking during the hand. It may have been too late to prevent the undue influence by then, but she still needs to attempt to enforce the rule, if only to impress its importance upon the others listening in. (If you let this stuff go, recreational players understandably get the impression that nothing is amiss, and start imitating the practice.) When the hand was over, she should have called the floor to report what had happened, and the floor should have asked the friend to leave the room. Players might reasonably just get a warning for a first offense (even if it caused real harm), but bystanders should get automatically expelled for such interference.
I'd be mad, too, Kristi.