I have elderly relatives, he has always controlled everything, their bank account, making all phone calls doing all the orders etc. Certainly, like Zorro, she would never have considered making a phone call like this as he would have been be angry, although never violent (I hope) However, he is now very frail with memory problems and, with my encouragement, she is becoming much more assertive and he has had to accept it.
Zorro, do you have a relative or friend who could support you on the way I have supported my relative? There is strength in numbers and he will probably step back and let you do these things. If, however, as others have suggested, there is a deeper issue here, please do get help.
Have a look at this website?: www.nationaldahelpline.org.uk/
Best wishes