My grandmother is 75 year old woman who has advancing diabetes (in which she does not take care of), arthritis. And has survived from breast and ovarian cancer. She's never aware when she falls sleep. Even during conversation.She constantly is sleeping while speak to people or just while doing a normal routine. She her self is not aware of it happening. Sometimes she is sleeping the whole day.She has complain of feeling weak; whether it's to cold or to warm (when it's not); and when she tries to sleep, has a hard time staying to sleep. She is quite stubborn and does not listen to advice.
is she constantly falling asleep because some of her lack of sleep days or is there more to it?
Absolutely tell her doctor about this, it might just be medication related or it might be something going on in her brain.
Another thing, prescription medications can cause one to be sleepy. I remember when I first started taking blood pressure pills, oh my gosh, I was so darn tired I couldn't stay awake, had no energy... once the doses were change, it make a big difference.