Okay, well then we have to come to a decision on whether Sheila was calculated and sane, or unaware and deranged.
I've actually struggled with that difference at times. My own indication that Sheila was unwell are the various changes in her pics. We all alter, facially, over the years but Sheila was only young and not subject to such change. I think it was her last pic, or at least one, with her mother and the twins---standing, where I personally thought that she didn't look too well. This would have to be compared to a modelling pic of her sitting on a chair.
I know make-up enhances, but I could see beyond that.