How do I calm my husband?

Stop taking him with you

He can't control his agitation and anger, so why put him in situations where it can occur? Who wants to feel that way? It's upsetting for him. It's not fair to him. This is why he needs meds -- even if you never take him out -- it will help him and you.

If he cannot control himself in public then he no longer goes out in public. I stopped taking my father to lunch because he would loudly discuss his bowel movements. No one needs to hear that. His desire to overshare does not trump others desire for a peaceful meal.

Two things come to mind considering you checked dementia for your question. If your husband isn’t on medication to calm his extreme behaviors, he needs to be, it’s a kindness to you both for him not to be so out of control. Secondly, it may be time he can no longer handle public outings, it may be too much for him now. I’m sorry it’s gotten to this point

Either keep him home with a sitter, talk to his doctor about medications for his agitation or you can hand the folks he's hollering at pre-printed cards explaining that your husband has dementia so they can better understand his outbursts.
You can probably order those cards from the Alzheimer's Associations website.
But in all reality, it's probably best that you just keep your husband home and away from things that irritate him.

Don't take him out in public.

If he is behaving in this manner, it is only a matter of time before he will turn this unreasonable anger on you, if he hasn't already.

Talk to his doctor about meds to calm him. It depends what is causing his outbursts or his delusions.
He may be helped with anti-psychotics, or with sedatives, or with anti-anxiety meds. You may have to experiment before finding what works.

I see several responses here about handing out cards explaining dementia to people observing the incidents. These might be appropriate in situations that are just a little embarrassing/uncomfortable for people--I suppose those might include staring, mildly inappropriate comments, etc. Education is good. But when someone is becoming agitated and raising their voice in a threatening way, things are way beyond this as a solution. From the viewpoint of the stranger who is confronted, they have no way of knowing whether or not this person will become physically violent, and indeed, many dementia sufferers are still very physically strong and actually do become violent. This is very unfair to both the unsuspecting stranger and the person with dementia. They are yelling because they are upset and anxious. Certainly look into medication to help them stay calm, but if that isn't working it's time for them to remain in their familiar environment at all times.

I agree with suggestions of calming meds and also leaving him home, but another thing I read once for inappropriate behavior in public is you can print out small cards that read something like “please excuse my husband’s inappropriate behavior. He has dementia. Thanks for understanding”

Stop taking your husband with dementia out in the public. There may come a time when he will throw something, like hot coffee, at someone with his anger and cause injury you will be responsible for.

Medication may help, but it’s better to place your husband into memory care.

Don't take him out. You can hand out cards, but people may feel their time is being infringed upon and should not have to be confronted by an angry person dementia or not.

We had an elderly hospital volunteer who threw a cup of water on a person he imagined he had a disagreement with. The volunteer office ended his service for that day and sent him home. I don't think he was allowed to come back after that incident.