Exercise for dementia?

ETA that I checked out the study you referenced, and it seems to be a good one.   My only hesitation would be that personal information has to be provided, apparently online, and on an open site, something which I abhor.  

And frankly I wouldn't want information about myself and/or someone for whom I'm caring who has physical limitations to be provided as a screening action on a site that isn't closed or protected in some way.    That could be an invitation for nefarious activity, such as including dates of funerals in obituaries.   From what I've read, those can be exploited by criminals.

I noted also that information on those who don't continue would continue to be kept, confidential, but what really can be confidential once it's been provided online?    Anyone who believes that should do some serious research on how data is stored and used.

Another concern, which I haven't explored, is that the study is being provided as a "Small Business Innovation Research grant through the National Institute of Aging and the National Institute of Health."

What specific businesses are involved?   I wouldn't consider either the NIA or NIH to be businesses.   And what kind of "innovation" is involved?

I also wonder if the study is relying at all on the experience of an organization  such as Mark Morris' one, which has established a reputation and has the experience of talented dancers, who I would think know more about safe movement than researchers.

I did jump ahead to an entity involved with this study:

https://www.togetherseniorhealth.com/about-us

Did some background checking on some of the people.  One has a good background in dance.  Another is an engineer with software experience.  I'm not sure how he fits in, but that did raise an issue I've seen with companies getting into the health care field and acquiring data on individuals who are somewhat health compromised:  marketing.  

I found out about venture capitalist involvement into the health when I had cataract surgery.  Long story made short, I wouldn't provide information online b/c after much research I learned that a venture capitalist allegedly "maintaining" the health care info provided was involved in data gathering, felt constrained by data silos which prevented sharing of health information.   That did it for me; no way would I contribute personal health information to an outfit with those goals.

Do your background research if you decide to participate in this study.

Responding to Alva's insights on balance, I would suggest that you explore the Dance for Parkinson's  site.   It's a program started by ballet dancers to reach out to people with Parkinson's, as well as others with balance issues, and just generally, to older folks.

https://danceforparkinsons.org/

Despite the program name, it's not limited to those with Parkinson's.

Click on the video on the left and you'll see people in a variety of movements, while standing or sitting.   A lot of the movements are basic but controlled stretches. 

This is a good beginning, just to get acquainted with the movements, whether standing or seated:

https://danceforparkinsons.org/resources/dance-at-home/welcome-page-for-dance-for-pd-beginners 

The program has spread throughout the states and beyond into other countries:

http://danceforparkinsons.org/find-a-class/class-locations

(Folks are dancing in the US, in Europe, in Australia, Africa and South America!)

You don't have to consider a class though; at least one of the DVDs is available on the website (upper left hand corner) and more are available through direct purchase.  

There used to be many more tapes of classes, but I can't get to the section today.  Perhaps there's a problem with that portion of the website.

Certain degree of physical exercise benefits everybody. This is paramount in the elderly, sick or healthy. The problem to consider is the propensity of falls that affects the old people. Those with dementia suffer balance problems caused by the dementia in addition to their age. I believe that there are safe, stationary exercises for incapacitated old folks.

I would only caution that you want to pass this by his MD. If there are balance issues you can be in a bit of a pickle with balance exercises that require a good balance. You don't want a fall and injury. Chair exercises are often a good option. Talk with his MD and good luck.