How to deal with an angry friend?

If a friend is in a state of anger (with someone else or you) and has vented that out on a text, let that text sit “unread” for some time.

Most likely, the friend would delete it.

It would let them not be embarrassed, understand that it is in calmness that things happen, and you won’t give them that anger back – which is a beautiful beautiful way of breaking the chain.