The fall she had in 2011? 2012? that caused the concussion was probably caused by having Parkinson's. My dad had several falls before he was diagnosed.
Correct about the freezing. But the disease can easily last 10-20 years if she just got the diagnosis. It actually gets worse faster with aggressive treatment. If you just do the dopamine replacement at the lowest level possible then you keep going albeit with some symptoms like muscle control problems including freezing. Basically that's because it many cases with late onset (as opposed to early onset) the disease does not destroy all of the brain's own dopamine production right away.