I've searched this but it doesn't to be an idiom and I just don't understand it. It's from the same Irish book I'm reading, could it be an Irish expression?. Here's the full sentence. I hope somehow can help.
(We = the main character and her boyfriend, John)
We were at my parents' for dinner. My father's veins were at him, my mother had a headache. John put on a brave face while surrounded by misery.