NoM, all I can offer is sympathy. I never cease to be shocked at what families can do to each other during the last days of a loved one. I've been stood in the High Court physically separating brothers from killing each other.
My advice is to rage silently. Take it out on something that doesn't deserve it, but won't care - like some dough, the garden, whatever. Then maintain dignified detachment.
I hope that the estate gets sorted out properly, but if the witch decides not to play ball, there are tools in your armour that I can arm you with should it be necessary.
Oh, and now I'll ditch the calm lawyer broccoli. Try not to lamp the witch in the face. Just get a wax dolly and stick pins in it til you are blue in the face. Otherwise, just drink wine...... Hugs. xxx