If the deceased had an heir, that heir would display the heraldry without any change, since it belonged to them now.  If there was no heir, then nobody owned the heraldry.

Just because somebody dies, their heraldry doesn't change.  Grave markers and effigies show the arms as they were, and don't add or remove anything.  If you want to display the arms of a deceased person, I suggest displaying it surrounded somehow by a black drape.

I'm also interested in any corrections offered by more knowledgeable heralds.

Gold Falcon, but not the most knowledgeable herald in the room...

>Was there a period way to display the heraldry of someone deceased?
black bar ??

I'd be tempted to say, yes there is, on the shields, garb, and other
appurtences of the heir(s) without any change in the amory, but I'm willing to be corrected by those who know more.