Nighttime sobbing. Anyone else observe this?

My mom, age 96, has dementia and my sister and I care for her in her home, 24/7. Lately she comes out of sleep sobbing. She seems to be in a light sleep state even though her eyes are open. It takes a few minutes to stir her out of it, talking and making eye contact. Then she is ok, and proceeds with whatever is next, getting up to use the bathroom, etc.

Anyone else observe this?