Sorry you are going through this... I know that you can validate her emotions. My wife is VERY tied emotionally to our house. Its her nest, security, ect ect so if it doesnt look right it is source of tirades,
We have lost a homes (twice due to crazy landlords) in the past and she has had incredible anxiety and rage over it . Still brings it up when raging even though she knows that it wasnt our fault when not raging.
Financial issues are tough in a normal non relationship. I am probably being a little stereotypical but women in general place high emotional stakes in the home so it must be that much worse for the BPD wife.
I had to do all the heavy lifting with the hard financial issues (still do ) and yet my wife handles the day to day finances very well. Yet she couldnt make a hard financial decision to save her life.
Try validating the emotions using SET .