Hello, and welcome to Mayo Connect, a community of people and caregivers living with a wide variety of diseases and conditions, who support each other along the way. We try to be informed medical consumers, and our own best advocates in our care. We are not medical professionals, so not able to provide medical advice. We can tell you what has worked for us (or not) and provide you with information and conversation about your questions.

I don't have direct knowledge of the unresponsive episodes you describe, but I remember how frightened my Grandad was the first time it happened to my Grandma - fortunately, they were living in a skilled nursing facility at the time, and the staff laid her down and elevated her feet, and she awoke - with no memory of the event. I was a busy new Mom at the time, so never did learn if there was a diagnosis.

Here is a related thread on Connect, it seems to suggest dehydration as a possible cause. https://connect.mayoclinic.org/discussion/parkinsons-unresponsive-episodes/
And a case study that suggests transient low blood pressure: https://clinicalmovementdisorders.biomedcentral.com/articles/10.1186/s40734-018-0068-4

Without moving your Mom, is it possible to check her blood pressure and do a "pinch test" to see if she is dehydrated when she goes into this state?
Sue