Hello @howardk

I am sorry to hear of your wife's diagnosis of breast cancer. This sounds very difficult to find the right chemo while having Parkinson's. On Connect, there is a discussion group where other PD patients have discussed taking chemo for cancer. Here is the link to that discussion
https://connect.mayoclinic.org/discussion/parkinsons-and-chemotherapy/
Have you considered getting a second opinion at a interdisciplinary medical center? Whenever you are facing a complicated health issue, a medical center like Mayo Clinic or a university medical school can be very helpful.