LOL
Funny thing is, if there is time, my wife loves to do a similar thing.
Say, on a weekend, she will wake up at 7 or 8 or something equally ungodly (annoying me, because IF i get to sleep, I love to sleep in).
Then she proceeds to wake me and have breakfast.
After breakfast, she goes back to sleep for an hour or two.
She calls this her "taking a break from sleeping".
Of course, I am left awake after the breakfast, as I can not go back to sleep.
But yeah, if this form of insomnia persists, I will need to devise a strategy, and your mom's sounds like a good one. This is new territory for me, as normally, I could just not go to sleep at all.
::emp::