Well, the assumption I am going to make is that this person really means a lot to you. I wouldn't think you would wanna live with this person otherwise. So, assuming that this person is a companion or friend who means a lot to you, I would suggest the following.

First of all, you'd have to learn to stay calm with a person who loses his/her temper at the drop of a hat. Responding the say way (in anger) only serves to exacerbate the situation with these kind of people. Perhaps, its what they want too - to have a confrontation. Maybe its their way of dealing with problems. However, if you stay calm in such a situation - you'd find that the person would feel like a fool after some minutes of shouting and throwing a tantrum. Most likely they'd apologize for their behavior.

So, the key is to ignore (if the anger is directed at you). Perhaps, just leave the room so you don't get tempted into making counter arguments. Believe me, counter arguments aren't gonna work coz they wouldn't be receptive to logic when they lose their temper. Anger puts blinkers on their eyes - they just can't see logic in that frame of mind.

If however, their anger is directed at someone else, you'd have to step in and be proactive. Try and get them to calm down by distracting them by a chore they were supposed to do or some other thing that they were supposed to get done. Get them out of the immediate area of confrontation - so that there is no eye contact between them and the person at whom their anger is directed at.

In the long term, getting them to attend Yoga classes would be very useful. Meditating helps calm the mind and conditions the mind. They'd perhaps not lose their temper so readily after they've done a good amount of Yoga sessions.