Oyakua - what you describe as happening to your mom sounds like narcolepsy (look this up on the internet; it's not insomnia-related) which can vary in its severity. It's just odd that it would show up at her age - usually it occurs in younger people.
She should start by keeping a regular getting up and going to bed time (what Drs call 'sleep hygiene'), take a little light exercise each day and perhaps keep a journal of her sleeping habits, emotional feelings etc. Try to help her with a healthy diet too.
She's on a lot of meds as you say and sometimes new meds get added by a Dr who doesn't really know the history of the patient and what's gone before. So it would be a good idea for her (and you if it would reassure you) to sit down with her regular doctor and go over her meds, what they do, how much and how often she should take them. This doctor also needs to look into what's happening with these 'sleepy' episodes - it could be to do with the meds or something else.
One of the worst things that could happen is that she has one of these episodes while driving.
I know you know her smoking won't help with any of this and that's a long and tough battle, but giving up may help.