My landlord and his girlfriend get drunk every night and fight

Okay, so why is this your problem?

You haven't asked a question.
You want to get out of your lease? Just leave, and hope they will be too drunk to track you down and sue you.
Make a sound recording of all their fighting in case they do.
Ordinarily I would go the legal route but it's too risky, if they are mean drunks.

And they have every right in America to do this. If they are too loud, or disturbing you you can call the police.