Her lachrymose demeanor was understandable given the loss of her brother; indeed, most of us were rather dolorous.
The words lachrymose and dolorous are adjectives that are used to show sorrow or a somber mood. lachrymose means tearful while dolorous means expressing great sorrow. In this instance, we can see that the people in this sentence were grieving the loss of someone. Her brother had died and it was a sign of sadness. She could not show happiness as she had shown before considering her loved one had passed on. We can also see that the rest of the people were also not in a happy mood and were also grieving.