Do elderly with Parkinson's use grip in their fingers?

Yes it is part of Parkinson's, because the nerves that control the muscles are deteriorating. Have a long chat with her MD about what to expect down the road and what kind of home care he can order for her.

YES! Parkinson's disease affects motor function in muscles and the dopamine necessary to work those muscles gets depleted in Parkinson's. This is the disease progress and only gets worse.

My mother has parkinsons too for 5 years now, she is 86, she lives in a retirement home near me , and they take wonderful care of her. She is on Hospice going on 5 months now, she can't walk, barely talks, and is so thin, we though in the begining we were going to loose her, that was in May of this year, now she is eating really good but is so frail and thin, sleeps most of the time. Sometimes when I visit her she is like in a cocoon position, is this nearing the end? But her appetite is really good and most of the time needs to be fed.

Yes, because of the tremors associated with Parkinson's, I would believe it would be hard to grasp anything.

My mom has LBD, and she is starting to have difficulty holding her coffee cup.

Unfortunately yes it is part of the disease. Parkinson's like a few other diseases effects the motor function.