Hello again
@Puzzleman, when I said there wasn't enough detail I was wandering if what you were describing was a sudden onset of symptoms beyond the norm for dementia. If that happens an infection can often be the cause.
Much of what you describe is standard for my experience of dementia. People with dementia may often seem unwilling to do things like taking exercise and keeping to a good diet because they just can't think to do these things and cannot see the benefits. I have a constant struggle with my wife on all fronts. I'm determined to keep her as well as can be but her tendency is to just sleep all day and not care about anything as I do it all while she thinks she's the busy one.
Don't fret about the memory - just keep repeating. If I speak to my wife she will have forgotten the start of a sentence while I'm still in the act of finishing it. The truth of this is that damage to the hippocampus results in the person not being able to process information so they don't make memories - it's not that they forget. This is one of the reasons a person with dementia will often seem to live in the past - long term memory is stored in another brain area that tends to remain intact until later stages of the disease. Another reason for this living in the past is that they are seeking comfort in reliving a time of their life where they felt more secure and in control.
On the communication front you can get a lot of tips from the thread that can be reached by clicking this link
https://forum.alzheimers.org.uk/threads/compassionate-communication-with-the-memory-impaired.30801/
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