I have just finished reading an article about this case in the Sunday Times.
Ian Brady has been force fed for 13 years, starting when he nearly succeeded in starving himself to death.
Recently he suffered a seizure which meant the force feeding could not be continued and he has once again got to starvation levels. I think that is why he informed Powell about the existence of a letter in his papers which are in a secure place.
Incidentally, whether or not you think someone should be an advocate for IB, she certainly seems to be suffering for it now. Seems although she informed the police of the letter a couple of weeks ago and was interviewed for over an hour and they weren't all that interested then, recently they raided her house, man-handled her and her teenage son, called her scum and removed all her computers and papers, took her out of her house in handcuffs and are now searching her house.
I think she has had to go into hiding.