If you must stay there for a while, you will have to, have to, have to realize that you can not deal with these issues for your parents. You will really have to learn that you can not do anything about your mom coming home with 1 or 2 beers in her. It is what it is. You know it's going to happen, so try not to be so let down when it does. You are setting yourself up for disappointment if you are expecting something else, even though you already know it's going to happen. If she comes home with a few beers in her....she does. You can't change that.
If you come home and find her naked on the couch, try coming in a side or back door where you literally don't have to walk past her. And then DON'T! Don't look at her, just go the other way and go straight to your room. Is that an option?
Do not threaten your mother, you can not make her go to sleep and her going to sleep is not going to change the fact she is drunk. It also is not going to change tomorrow. You have to realize that you can not change this situation and that whatever altercations that comes out of your attempts are only going to look bad on you and then make you feel worse about yourself --- because you will feel guilty for your actions. I would say your biggest challenge right now would be to do your best to learn to just accept it for what it is, you are not going to be able to change this situation. Stay out of the fights, stay away from the drama. Make GOOD friends, not just any old friends to get you out of the house. Try to find another job, concentrate on school, etc. positive changes to YOUR life. That's the only thing you have the power to change...yourself!
Work hard to make yourself feel better and to build a plan to get out. This is not your responsibility and no matter what you try to do, you will not be able to fix it. Your parents think it is normal behavior because they are both sick, you can not reason with people like that. You will not get them to realize it is them and not you. That will not happen. Stop trying. I have been in your shoes. You will not change them, you can only save yourself. I promise you.