There's a corollary of the #DontFeedTheTrolls principle for social media; when someone loses their temper at you, or talks down to you, that's also trolling. Don't dignify it with a reply.
Even when it's someone you normally get on well with. Even when it's someone you know in person.
Maybe use the time you would have spent wording a diplomatic reply to reach out to them in private, and ask them if they're OK. But don't throw fuel on the trashfire of their grumpy outburst. It never helps.