I'm beginning to doubt that Grandma woke up late. I don't think she went to bed at all. If she and a friend were partaking in meth or other amphetamines, it's not unusual to miss a normal sleep cycle. "Staying up all night" can also mean being too wired to sleep for many, many hours. I don't doubt that Grandma was "distracted." Perhaps she told LE she slept and awoke to minimize her impairment. Or, maybe she was giving herself a few hours to "come down" a bit and not appear to be a "tweaker." IMO