My sister an I live together. Last year she was diagnosed with early onset Alzheimer's. She is still able to take care of herself but she has stopped reading and painting. She is still teaching art lessons. But most of the day she sits in her bedroom and watches TV. The only time she leaves the house is to go to the grocery store. She recently started a new painting and worked on it for 30 minutes before returning to the TV. I don't get it! I've stopped trying to convince her to find other activities but finally gave up. I don't understand the TV addiction.
She must NOT drive.
Do know that the constant feed of TV sound is not uncommon for the WELL. I have both a stepdaughter and a good friend who must have the TV on 24/7 night and day. Go figure. Or, wait! DON'T.
I recommend reading as much of Oliver Sacks as you are able. He loved all things to do with the mind. Wrote a whole book about music and the mind called Musicophelia. He said that those with Dementia have entire worlds in their mind. They just are not OUR world. So watch. Take up a fascination. But don't expect to understand.
Then I will say that your sister can no longer read nor comprehend what she's reading thus why she's stopped reading. That is sadly one of many things one loses when they have a broken brain.
The fact that she's choosing to watch TV 24/7 is not an addiction but it's more of an escape from their reality and often something that they can follow without too much effort.
Perhaps it's now time that you educate yourself more about this horrific disease of dementia so you can be better prepared for what is to come as early onset Alzheimer's can go on for 20+ years.
My late husband who had vascular dementia and hadn't been able to read since his massive stroke at the age of 48,(he died at 72)kept the TV on pretty much 24/7 the last 5 years of his life. And his shows of choice were usually the action packed ones that he could easily follow without having to use his brain much.
You are in for a very long and challenging journey with your sister, so I hope you and her get your ducks in a row now before she gets worse as guaranteed she will.