How do I survive and maybe forgive abusive elderly parent?

My wonderful mother finally convinced me she needed me to move back home to live with her. She was persuasive, So I did. I quit a wonderful government job (where they loved me) and moved back to the USA to move in with her.

My brother has his own apartment in the house and has done his best (really). My Dad died six months ago and my mother's hoarding has kicked up tenfold. In the space of two weeks my mother has changed into someone I don't know, she is vicious, hostile, lies non stop, and she has called every health care provider, lawyer, government agency she can contact to say my brother and I are abusing her. Evidently clearing up ( the garbage only), offering to pay all her debts and take over all expenses for the rest of her life makes us the worst children ever. And we were delicate about it, as she is losing her touch slowly but surely. She now states I have to move out immediately, she has changed her will and slandered my brother and I to every personal contact and our family. We are on the title so although awkward and quite scary sometimes, we are not going to be run out. She is articulate, presentable and a consumate community leader in public, but at home she's become bizarre and threatening. We look like the bad guys. Yesterday she removed the bed from my room. She refuses any kind of counselling. What happened?