Jeremy knew the family routine. Sheila had stayed at the Farm previously though I can't recall whether the twins were with her or staying with Colin at the time(this proves that I don't have all the answers at my fingertips).
I'm not entirely sure that this is correct, but it seems very likely that Sheila hadn't spent time at the farm with the twins since prior to the previous Christmas when the onset of psychosis prevented her from being there. Which apart from giving Jeremy no opportunity to establish what was "routine", and given that according to you he was fuelled up on cocaine and dope, he would hardly recognize a weekly routine, let alone a twice yearly one.
My other point is that you maintain that Jeremy left Sheila hoping she would belled to death before she was found. Wouldn't you have thought that having fatally dispatched 4 people Jeremy would have recognized DEAD when he saw it.
