I have to disagree scipio, Pamela stated that June told her on the telephone how worried she was about Sheila's lack of interest in anything including the boys just as Jane stated in her post. It is in fact one of the very few things we definitely know about the night of the murders.
What someone sees as a lack of interest is in the eye of the beholder. There is a reason why courts don't want witnesses to give subjective opinions but only want witnesses who cant detail events they observed and conversations they had so the trier of fact can draw their own conclusions.
I gave 2 examples of things we know happened- one was her taking an interest in washing their clothing and another is she actually went with them to visit Jeremy which he complained about because he said they were bothering him. It is clear at least some of the time she payed attention to them while they were visiting.
It is obvious the Haldol affected her as she had speech problems and sometimes would just sit around vacantly but she wasn't like that 24/7. It was concerning but different than if she were like that always which would have resulted in her doctors being consulted.
It seems June and Nevill wanted Sheila to entertain the boys most of the time and just to have a little bit of time with them which makes me wonder why they even wanted them to stay over.