Medication Use in Older Adults

My dad takes 21 medications up to 3 times a day! He's not doing well at all. Ever since he's been doing this at a nursing home he's been unable to walk because he shakes too much and looses balance so he's restrained to a chair. He's unable to talk because he's slurring and out of it. He's unable to eat by hisself. He's only 64 and has dementia. Everyone just thinks that his dementia has progressed due to his symptoms. They don't think that it's because of his medication that's causing his symptoms. Now everyone wants to sign a DNR form.

Why is a lower drug dose indicated in elderly clients??