I'm not sure on what to say. I've had alot of friends' parents go through fighting and what I used to say is "wait it over" because I thought you know, that they'd get over it. Sometimes it works, but other times you need to argue your point a bit and try to get them to make up.
My parents got into a HUGE fight once. I mean, it ended up with both of them storming off to their cars and leaving me alone with my brothers for half a day, before my dad came back. They never spoke to each other for three months and I was terrified. I loved both of my parents alot and I couldn't stand the thought of them living apart. So for three whole months I argued that they couldn't divorce and how they should stay together not for our sake, but for their own. They rely so much on the other and they'd be lost without each other. Throughout the summer, I was basically keeping my parents' marriage together.
Towards the end of it, my dad walked home with a stack of papers. I flipped out. I grabbed them when he wasn't looking and read the top of it. Immediately, I took it downstairs and shredded it. =] Can you guess what it was? It was a claim for divorce. My dad eventually noticed that it had gone somewhere and asked me where it was. I told him that him that I shredded it and he said that if I gave him the permission to, he would file a divorce. He also then asked me if I wanted him to talk to my mom for the first time in months. Of course I did! So, after an hour or two of them just talking, reminiscing about how they first met, they finally made up. I was just really happy then.
So, what I'm really trying to say is that you should just try to give them your point of view and help them talk it out because it might work out in the end.