Dealing with an angry friend or acquaintance

I am  not talking about accepting violence and abuse from partner’s or friends
Similarly to Gandhi’s peaceful resistance, I  think we need to avoid immediate retaliation when a person is angry while maybe removing ourselves from the scene for a while.
Because a number of health matters can make people fly off the handle.The one I know best is diabetes.But the angry person might not yet be diagnosed.Depression can make people irritable too.Fear can display as anger in men.A problem at work  can make people desperate
My husband was diabetic and at one time when we were eating, he would begin arguing or even shouting.After studying diabetes in depth I found he was having hypos; very low blood sugar.So I started giving him some light food at 4 pm.Then he was back to his usual self.But I do think doctors do not inform us.I bought many books and even a glucose monitor.I practised on my own hands for 2 weeks [ somewhat painful]  and then I began to test him.He said I was better than the nurse.
The little instrument with which you pierce the skin has a small sharp point.I got fed up with it being hard to work, so I took the needle out and just stuck it into my finger! That got some blood out to test,
Don’t do this unless you are desperate.