Mike, there is NOTHING, in the extracts you have posted,which relates in ANY way to each other. That which you speak of as being a difficult to read, hand written note is beginning to turn into a fictional BOOK and you can't have it all ways. The first extract was totally believable. The rest isn't but as you say, it was difficult to read so we have to allow that you read it wrongly.
Yes, Sheila became very distressed in the middle of the creation of the note, her handwriting becomes enormous and almost ineligible...
But...
From what I can glean from its contents, Sheila appears to be upset about possibly having her birth name (Bridget) changed into Sheila, and at the time of writing the note, she speaks about expecting the police to be arriving very soon, to sort out some messy business or other, and she is not happy with her ex husband for one reason or another, she is worried about her mother losing strength and slipping away, and that she needs help but Sheila won't be able to give it to her in the afterworld...
If Sheila is the author of this then, it looks odds on that she had lost the plot, had been contemplating the imminent arrival of the police, had a bee in her bonnet about her ex husband, was worried about her mothers strength slipping away, and that talk of not being able to give her mother the help she needed from the afterworld where she was bound, might provide an insight into the state if her mind at the time the other four members of her family were shot by her..,