Horrible Bosses

Sorry, I need to vent.

There are countless examples of my boss being pissy. I am usually able to ignore his negative attitude so as not to get myself in a bad mood but today really rubbed me the wrong way. My mom called and told me my uncle likely won't make it through the day. I told my boss and without looking up from his computer disregarded me with a "Sorry." I want to be with my family but since this seems to be no big deal to my boss I guess I'm expected to sit here until quitting time and by then it will likely be too late. I don't know what to do. I can't do anything crazy because I can't get fired.