The picture isn't clear enough to tell if that is a man's slipper whereas the other one is.
Nonsense. The photo is blurry plus the shoe is half hidden under the bed- we can't see the front of it which for all you know has a bow on it or was pointed thus indicating it was definitely a female's shoe.
It is your unsupported opinion it is Nevill's shoe, indeed if his shoe had been in there police would have been likely to note it.
You take this unsupported claim then craft around it the notion Sheila slept with her mother which is absurd. She was a grown woman not a child. My paternal grandmother and adult aunt slept in the same bed only after my grandfather died and even then only when they visited a place where there was only one spare bed so they had to share it or if so many people visited my grandmother that my aunt gave up her bed to the visitor and thus slept with my grandmother.
When we were 10 or so my grandfather was still alive and we stayed over because our parents went away and we stayed in my aunt's bed with her. She didn't sleep with my grandmother and us with our grandfather.
My maternal grandmother never shared a bed with my mom. My mom would have to sleep on the floor if there was no room anywhere else.
The notion Sheila wanted to sleep with her mom for comfort is just absurd.
If that had happened then Jeremy would have been screwed because Nevill would have come from the other room and disarmed him. He shot Nevill's while Nevill was not facing him. He shot Nevill's left profile as Nevill was getting out of bed.