I agree with you there, except maybe in this case she had given the child a cough suppressant that makes babies sleepy, so she assumed Lisa was asleep.
I don't know.
I will say, there is a HUGE variability in families with when they put their children to bed. For us, small school children (K - 2) went to bed before 9 on school nights, anyone younger or older might have had a different schedule.
If I'd have put my 10 month old baby down at 6:40, in the absence of cough medicine or serious illness, they'd have screamed themselves sweaty after awhile. My babies at 10 months didn't go down until about 10, so they WOULD sleep until 6:30 a.m. or so.
But I've learned every family seems to keep different hours.