There is no way of knowing if Sheila was asleep or awake, we can see that when the photos were taken it appeared neither of the beds in Sheila's room had been slept in although one showed signs of having been lain on at least for a minute. That is all we know about Sheila's room. We know Sheila as a PS may not have slept well at all, this is a definite and very common side effect of the condition. We also know Sheila may have slept because of the Haldol but that doesn't always follow particularly in Sheila's case when her dose had been cut and she was nearing her next dose, we also know that she would have had a build up of the drug in her system. At pm it was obviously found she still had Haldol in her system but we don't know how much, there was no other sedative detected. The conclusion from that is, we just don't know the answer to whether she could have been awake or asleep imo.
Dependent on what time Neville was ready to go to bed,Sheila may possibly have sneaked into his place until he came up the stairs,Sheila sharing Bible readings with her mother,quite possibly from the verses which signified her thoughts at that time,Good and Evil. Wherever anyone happened to be,the Bible came into play. There were about 5 which had been placed in strategic areas of the farmhouse.
This would then have accounted Sheila's bed as not having been slept in. I think Neville would have perhaps showered in the meantime then made sure that everywhere was locked up and safe-------------------------then what ?
Well Neville would finally have gone upstairs,Sheila would then have moved from their bed and gone to lie on top of her own bed,obviously awake, or she'd have gone under the covers. Why didn't Sheila get into bed ? Where did she go when she got up,as she wouldn't have lain on top of the covers all night ?