My Mom's eyes looked huge and kind of buggy. Can there be an explanation for what we saw?

Is she administering her own Xanax? With short term memory loss, that you be a problem. It may be time for something more systemic, like an antidepressant that has anti anxiety properties. Talk to her doctor, or to a geriatric psychiatrist, if you have access to one.

That could be it, Babalou. She seemed better recently, except for the dementia, of course. I wonder if it's too many pills sometimes. Some she needs, but the xanax and stuff, maybe not so much? Except she does get wound up easily, so there is a need for xanax.

Is it that she's disoriented when she wakes up, not really knowing where she is?

Her dementia isn't too bad. She has bad spells where she'll imagine something. She does have access to the xanax, but she usually takes it before bedtime as she mostly likes it for sleep.
And no, didn't check her blood sugar level. She's been having a home nurse visiting a couple times a week for the last month and they'd checked on her today. They call me if they have questions or concerns. She just looked kind of huge-eyed, and she has in the past after waking from a nap. She seemed good other than the big eyes. Planning to check again on her in the a.m. She said she felt fine and everything, so there's that. But it was just odd to see.

Did you check her blood sugar level? Besides,xanax what else is she on? Does your mother have access to the Xanax herself? How advanced is her dementia?