Of course not Alias,when there are people on this site who know better 
June told Pamela that night that she was very worried about Sheila's health just before they all died. Whatever happened that night one of the few facts we do know about that night is that June told her sister at about 10pm that she was very worried about Sheila's behaviour and wanted to speak to her the next day about it.
I've never argued with ANY of you regarding Sheila's emotional and mental health. IMO, that she was not being monitored after her meds being adjusted was a potential recipe for disaster and that's just about the chemicals. Her emotional state was something other. She wasn't having regular counselling and the meds, unless they turned her into a zombie, wouldn't have helped that. June had every right to feel concerned. She was an emotional mess which makes it FAR to easy to pin the murders on her but how COULD she have done it? Where were all the bloodied clothes? Yes, she could have showered. Yes, she could have washed her hair, but WHERE were the clothes she wore?
I'll bet she'd never loaded a gun in her life. If she'd EVER used one, someone would probably have loaded it for her -I believe it to be customary at shoots- so IMO, it goes without saying that she wouldn't have been able to load a weapon she'd never seen before, but she made a very convenient scape-goat.