Son has taken away his father's TV and phone. Cut off airconditioning, won't let him see anyone. Stopped people from coming and taking him to church. There appears to be something wrong with the running water. He now has to get water from an outside well. The man is obviously afraid of his son and says his daughter yells at him all the time. They live on a back road so there are no neighbors as such to keep an eye on these things.
It wouldn't surprise if they do, but as FF points out, you'll want to be sure before calling in APS (Adult Protective Service). In Michigan, they're generally county oriented, so you could google your county, and APS. Your municipality or county may also have a health care department with a social worker who might be of assistance, but APS has the authority to investigate and take action.
Please let us know what you learn as to whether or not the deplorable situation is in fact how this poor man is forced to live.
If the father has dementia, there is a stage where they start telling stories which are not true. I suggest you take a ride over to the house to see for yourself before calling APS.