Sheila was medicated, there is no quick fix for greed.
Yes Caroline, Sheila was medicated to the point where she could barely pour a cup of coffee without spilling it, as you know
She was also sensitive about her appearance, but just days prior going to WHF her friends said she had difficulty applying her make-up properly. They said it was all a mess, smudged everywhere — and on the day Jeremy murdered them the shopkeeper where Sheila and June took the boys to buy jeans said Sheila had smudged red lipstick all over her teeth: which alone proves how unsteady her hand movements were that day, and how unaware she was.
Besides that, Sheila was never greedy. She never pestered her parents for handouts, and took jobs that were well below her capabilities had she been well; she never begged/demanded financial help from her parents. She tried to work (for a minimum amount) rather than sponge off them because she had pride, decency, and was not a sponger. Nor was she lazy...
She was the polar opposite to the lazy, begrudging, demanding Jeremy who resented working and decided to become BOSS of WHF by murdering them all.
And a minority of people say he isn’t a psychopath?!