slb340,

Welcome to the forum. I am not a doctor, so make of what I write as you will.

Every PWP is different, but:

IPD normally progresses slowly over the course of, perhaps, 20 years. Sometimes another illness, like the flu, leads to a step-change in the PD.

IPD normally responds well to levodopa (at least for a few years).

To go from "mild" PD to the stage where walking is difficult in just a few months is unusual.

I suggest your mom sees her GP about her general health and her neurologist about the diagnosis. Has she had a MRI scan to exclude other conditions such as stroke?

IPD stands for idiopathic PD: PD of unknown cause. This is what is normally meant by just "PD". There are many other illnesses which at least to start with have similar symptoms, e.g. vascular parkinsonism.

John