Wow!

I, too, was fainting and falling for over a year before my neuro ordered a tilt table test. My BP dropped over 20 mmHg when standing, and probably drops more when walking. After that Neuro ordered DaT scan which confirmed PD. Your cardiologist or Neurologist should order it or if you have a good relationship with PCP they can do it
I had a pacemaker but that didn't help the dizziness although Haven't passed out anymore.
I was encouraged to heavily salt food, take 1 or 2 gram salt tablets a day, tried midodrine which didn't help and put on fludricortisone which seems to keep my BP over 90s systolic and no fainting or falls since

Could any of her medications be causing it?

I've been falling for years. My nephrologist put me on Fludrocortisone 4, 0.1mgs 15 years ago along with Midodrine 3 times a day. Up until this year I was still falling and was unconscious, in a parking lot with my 14 yo granddaughter, at my mail box in the street and at a local Whataburger counter. My cardiologist finally got me on Droxidopa (Northera) 300mgs 3 times a day. So far all is good. This is a lot of medication to pump my blood pressure to 110/70. Go figure...🙄

I got a galaxy 5 watch which you can put a line on like a phone. If it detects a fall and you don't respond it will call up to 5 contacts or 911. Plus count steps, take heart rate, blood oxygen, etc...