All the videos are saying the same thing. It would have been inpossible for Sheila to fill up a water pistol for her sons, let alone carry out a very impressive massacre and win a fight with Nevill.
It is true Haldol can cause awful side effects as shown in videos but not everyone suffers from all or any of these side effects.
Sheila may have suffered from some physical side effects particularly when she was on a really high dose but I would question that she was very impaired by such side effects and wasn't taking any drugs to counteract such side effects at the time of her death. I am sure Sheila would have taken such drugs if they were necessary.
She seems to have managed to live a relatively physically normal life. None of her friends who have commented or given statements mentioned her suffering from such symptoms which is significant imo.
Any comments have tended to be about her emotional and mental health difficulties.
We hear much about her manicured nails, make up she wore and smoking roll ups all of which require steady hands.
I don't believe Sheila murdered her family however I don't think there's any proof that Sheila was physically incapacitated by Haldol.