My question pertains to where and why you are in this familial relationship? My gut is to ask why are you in the home to begin with? You should not be part of this and, quite frankly, you should not be a part of their relationship to begin with. You should be on your own and their business ought to be their business alone. I think this is a terribly unfair position to put you in. A parent ought not to be using a child as a confidant. Were you to be on your own the relationship(s) you have with your parents I am sure would be healthier.

I'm afraid you are going to have to draw the line with your mom and firmly inform her you will not be brought into the problem in such manner. You need to put your foot down and tell her you won't be a part of this.

Personally I would not turn to your father. You need to refuse to get into the middle of this no matter how strongly you feel the urge to do so. This is between them. This is also their problem to resolve and choice to make. As I have said you should not take sides. But equally as important is you should not be involved in trying to prevent it. What happens happens and you need to be supportive of them once all is said and done.