My mom was diagnosed with vascular dementia and Alzheimer's a year ago. We knew something was not right with her. She did suffer a stroke a few years back that no one was aware of. We only found out last year when she had a CT scan. She was seen by a geriatric Dr. who did further testing. We did tell her she suffered a stroke. Should we tell her she has dementia? We don't think she will take it very well. She has always told us never to put her in a nursing home. When she forgets things or can't find something she accuses others of taking it. She won't accept the fact that she might have put it somewhere. This has happened with money, pills, jeweler, hearing aids, etc. she is always making up excuses.
She may not take it well because there is so much to accept and sadly not much can be done about it
Although my mom would parrot me and say she had dementia it in no way changed any of the troubling behavior
Dementia is a long tiring journey for everyone
You CANNOT reason, explain, or logically convince a person who has dementia out of a delusion. In your Mom's reality, something has gone missing. Her delusion is that it was not of her doing. Someone stole it. You MIGHT be able to reassure her that it was only misplaced, but not that she misplaced it. ("Mom, I know that neighbor Sally would not have stolen your scissors. but she might have misplaced it. Or I might have even accidentally misplaced it, so I will help you look for it. If we can't find it soon, let's just buy a new one.")
Your mom does not "make up excuses." She tries to make sense of her confusing world. If something is missing then one sensible explanation, in her world, is that it was stolen.
It sounds like at this point she should not have access to her pills. She may need more supervision when it is time to remove her hearing aids.
Before telling her that she has dementia, I suggest two considerations: 1) learn all you can about dementia, especially vascular dementia. If you want her to know she has it, you should be able to answer some of the questions she might have. 2) think long and hard about how this might help her or harm her.
We never mentioned the "D" word in my mother's presence. Denial was a reliable coping mechanism for her for decades. Why would we expect that to change now? My husband knew from the day he was diagnosed that he had Lewy Body Dementia. As an engineer who firmly believed in cause-and-effect, he needed to know what was causing his new behavior. Each person is different. Don't tell your mom unless you can see some benefits for HER to knowing.
Don't promise that you won't put her in a nursing home. Promise her that you will never abandon her and that you will always be her advocate (if that is true). With dementia it is not uncommon to need more care than can be provided in a private home. Don't make promises that would be counter to her best interests, but reassure her that you will always look after her.