The honest truth - if you're an engineering manager and you're no longer anywhere near the code then just at the heat of the moment there really isn't much you can do, aside from what you've been doing: listening on the call and doing a minimal check-in.

The main thing you can do is after all is over to make people feel awesome, give them recognition in all the ways possible: bonus, extra vacation days to compensate for the crunch time, etc

But if you still have your technical chops - jump in the trenches and debug!