Hi NewMe
I'm sorry for what you are going through... and I wish I could make it better, but I can't. What I can do is tell you what I see, and encourage you to come back to this information later on if it's too much to take in now. I promise that understanding helps...
The bad news is, your dad is committing a form of psychological suicide. What he's done is picked sides, and it's not your side he's picked. What he's gotten himself into is something that used to be called 'folie à deux'.
http://en.wikipedia.org/wiki/Folie_à_deux
http://www.gpnotebook.co.uk/cache/1033502722.htmhttp://www.emedicine.com/med/topic3352.htmThis is, I think, an extreme form of codependency. It comes from denial, sometimes from mental and emotional laziness, and always involves a fear of confronting the sick partner. Basically your dad has decided that he'd rather be nuts with your mother than sane without her because the price of being sane is higher than he wants to pay.
The good news, if you can call it that, is that this is to some extent both a compulsion and a choice. He probably is very dependent on your mother, if she dominates the relationship. He may very well recover from this if they were to be separated for any reason.
Thing is, they're not likely to be separated for any reason, and he's clearly made his choice.
Now - there is a lot of valuable free information in this situation, which will help a lot later on if you don't feel ready to take it in just yet.
First: your mother is slandering you out of malice. Look at the form this slander has taken... accusing you of getting something she wants. Wow, what a giveaway this is to anyone with their brain booted up! You have a perfect right to buy a Hummer, black or green or pink, if you want one. Leaving aside the ecological arguments
, the only kind of person who regards someone else's purchase of a vehicle as some kind of crime or personal affront is a very sick, very boundaryless, very envious person.
Second: sorry to say this, but prepare yourself to discover, eventually, that she has been slandering you out of malice for a long, long time. About weird stuff, little things, whatever. This sort of thing doesn't usually spring up full blown out of nowhere.
Third: again, sorry to say this. Prepare yourself to discover many more instances of your father being enabling and exhibiting mental laziness or emotional cowardice or whatever term for it fits your perspective best, i.e. refusing to see, deal with, believe, admit, confront what is going on with her, and refusing to support, hear, validate, understand, empathize with anyone that she is injuring.
Fourth: You are lucky. Not because they're doing this stuff but because you have at least some family members - your brother, which is amazing, someone in your FOO, a first degree relative! - who aren't buying into the nuttiness and are unafraid to stand up and announce what the reality is. This is very very rare. Usually a family bully manages to enlist the entire family in the mistreatment of their chosen scapegoat.
These are strong and direct words that I have used, and I'm sorry if they're too strong and direct for where you are now. I hope they're not, I hope this degree of directness is what you are looking for and what you can use at this moment.
Edit in: ahh. I didn't see Laura's post or your reply while I was writing. I'm sorry about your brother... this too is unfortunately not uncommon, that someone chooses to stay with an abuser because they expect to derive some sort of ultimate benefit from it.
It can be terribly sad, for instance when a battered woman has been so isolated from family and cut off from any source of income by the abuser that she literally feels she has no other option but to stay and be abused. [There is a sadness that goes down through generations in this case, because all too often this woman has children, and the children come to believe that she chose the abuser over them. Sometimes this is true. Sometimes, it's really the only option she thought she had - and then she loses, loses, loses. Marries an abuser, stays with him, loses. Has children, fails to protect them, loses... ]
It can be utterly infuriating, for instance when someone decides to side with a jerky abusive relative because they 'get something' out of it. They stand to inherit when the jerk passes away. Or an abused spouse stays with the abuser even though it is causing her children psychological harm, because he makes a lot of money and she likes nice things, or the make-up sex is good, or there's some other 'perk' that means more to her than her children's futures and psychological wellbeing.
And because it's a continuum, there are all kinds of shadings and situations in between the extremes of trapped helplessness and calculated self- and other-betrayal.
Your brother's situation is somewhere in between... and very very sad... he does see reality for now, but you should know that this may change. He will be forced, one way or another, to choose sides by your mother, and unfortunately it doesn't sound as though he's going to make a stand for sanity when that day comes...
But be glad that he sees reality now. That is comforting, at any rate.
