I have drug induced parkinson's syndrome as well. my prayers are with your mother.
I just saw your question. This interests me greatly because I'm beginning to think the same thing is happening to me.
I came across this article yesterday while doing some research; The patient was a 74 woman and the drug in question was Trazodone. After they stopped it, at two months she showed normal was much improved;
at six months her gait and muscle tone were normal, and at ten months the signs of it were gone. The url so you can read this is:
I thought it was extremely interesting! I have my next neurology appt. next week and it will be interesting to see what he has to say also..