I’m not saying as fact, but, devils advocate, could it be possible that JS has a condition that could cause fatigue? Maybe she was/is tired frequently… besides depression, maybe fibromyalgia or CFS or POTS? Has SS ever taken MS to school before? MOO, not fact, just throwing out some possibilities as no one can understand her being tired, but I get it. *yawn*
We don't know.
The thing that stands out though is it was mentioned--I believe in the grandmother's interview--that MS is *always* the one who took MS to school. JS also said when she said MS did not know her address, (paraphrasing) "She's always in the car with me."
So, I would think if JS did have something like CFS or POTS, MS probably would have been a bus student, or someone else would have regularly been taking her to and from school so JS could sleep in after working at night.
It's also not that long of a trip. I have had serious health problems, and it's pretty unusual as a mom to be so ill you cannot drive a few miles down the road. We tend to just do things like this even when we should rest, IME. It could happen, but the odds it happens on the same day your kid forgets her phone, goes missing and you either saw her last night at bedtime or at 8am that morning?