Welcome to the forum. To get to 26 years post diagnosis your wife must be doing something right.
Before commenting about the drug regimen it will be useful to know the time and size of each dose and each symptom.
In the meantime, you may be interested in this paper:
"An Elderly Parkinsonian Patient with Extreme Blood Pressure Fluctuations"
An Elderly Parkinsonian Patient with Extreme Blood Pressure Fluctuations - ScienceDirect.
John