Choosing to ignore that Haloperidol dosage was theraputic means it's easy to carry on claiming Sheila to be the culprit.
Jane, it's debateable whether medication dosages are therapeutic in lots of circumstances. The body and mind goes through all sorts of changes in 24hrs and whatever affects the body affects the mind also and vice-versa.
As in my own circumstances taking ( presently ) a therapeutic dose of warfarin, but that could all change and adjustments made after a blood-test which could register either above or below the International Normalized Ratio ( INR ) or bleeding time. This adjustment can be caused by all kinds of things, food, emotions, nobody knows for sure why it fluctuates. It's not failsafe and can cause internal bleeding. Warfarin doesn't agree with everyone.
In Sheila's case, her therapeutic dose should have been checked regularly particularly as she was a cannabis smoker which would have had its own problems within the brain, so although written up as a therapeutic dose it doesn't always play out because of lifestyles.
Sheila's initial high dose was administered for a reason ! But there again, was it the correct medication ? Or did it exacerbate her problems ? We'll never know. One man's meat and all that.