Mom with PD now has cognitive changes. Is this part of PD?

A BIG factor? Is on meds for PD. Speaking of things she used to do before PD as if she's just done them a few days ago. Also rambling on but mixing up names and events. Are cognitive changes part of PD? She is 86, lives alone and REFUSES any suggestions for help. "I know what I am doing". Is on PD meds, but I wonder if she takes correctly. Refuses help or suggestions. "I'll know when I need to go to assisted living" At this point, I doubt it. Balance seems worse.(slid off side of bed recently. 911 had to be called, no injury. I worry so and am so upset she won't accept help. Is PD more than shakiness? Are cognitive changes also a big part? I don't know what I am supposed to do.