My roommate passed away July 4th in a drunk driving accident. Her Mom is now openly blaming our other roommate on facebook for indirectly causing her death. Advice on how to handle this please, Reddit?

I tried to make the title brief, ...this situation is complex.

There were three of us in this house. Me, and we'll call the others Ann and Sarah.

Sarah was partying on July 4th, and unfortunately attempted to drive home drunk at 4:00am. She lost control of her car, struck a tree and died instantly. This has been a strange experience for me, as I never got along with Sarah and frankly didn't like her. I found her to be hateful, and highly racist most of the time. I feel terrible saying this after her passing. I feel very torn. I'm sad about her death, but still sour about how she treated Ann and me.

Ann had known Sarah for many years. I was a last minute roommate- didn't know Sarah until the day I moved in. Well as the year progressed, Ann grew tired of Sarah's behavior and irresponsibility with bills and rent. 3 weeks ago, Ann sat Sarah down and told her she had 30 days to find a new place to live (it's Ann's house). Sarah got angry and moved out the very next day. That was the last they spoke or saw each other.

July 5th around noon Ann received a text from Sarah's mother that read: "Sarah died last night. You don't have to deal with her anymore." (her mother obviously heard about their falling out) We were shocked to say the least. Ann lost it, fell to the ground, cried uncontrollably. I'm close with Ann. I tried to console her as best I could.

Yesterday morning, Sarah's mother posted a very graphic status on facebook. It described the state of Sarah's body when she was found, and stated that her death was caused by her being "displaced" by her roommates. The status was deleted within an hour, but it was too late. Ann saw it, and proceeded to break down again. I don't know what to do. It's totally unfair.

I understand that I, not being a parent, cannot begin to comprehend the pain of losing a child. I know Sarah's mother may say more irrational, hurtful things again. She is grieving.

But, please, what can I say to my roommate who breaks down every time Sarah's mom says something like this?
Ann was such a good friend to Sarah. Made huge sacrifices, and was patient to a fault. I can't stand seeing her be beat down like this.