My sister has dementia! We moved her into a board and care a year ago. She thinks she‘s in the home we grew up in. What do we tell her?

You meet her where she's at, and if she thinks she's living in the family home you just go along with it. People try to make this much more difficult than it has to be.
Life will be much easier if you just go along with whatever your sister is saying. If she says the sky is fuchsia, you just say and what a pretty color of fuchsia it is.
And because your sisters brain is broken it really serves no purpose in telling her that you're selling her home.
And when you bring her some of her things(if you feel it's absolutely necessary, as she may not remember them anyway)you can just tell that you found them in the "basement" and you thought she'd might like to enjoy them again, or that they were being fixed or worked on or whatever might fit the bill.
They're call "fiblets" and they are little therapeutic lies that will help keep the peace with your loved one.
Again, you must meet her in her world not yours, as they are 2 totally different places.

If she’s happy thinking she lives in the house where she grew up, you’re lucky. She could be begging to go “home.” Right now, she thinks she’s there.

Why bother taking her cherished items that her brain no longer cherishes? And the last thing you need is for those things to trigger memories of the house you’re going to sell, if such a trigger is possible.

The best thing you could do is to let her be who she is now. Keep your fond memories of who she once was. But keep them to yourself.

I wish you luck on this journey into new territory. It is what it is, and what it is today will be different than tomorrow.

That is a gift - accept her reality. Therapeutic lies are part of communication strategies for people with dementia.

As other have written here, do not say a word. Dementia has taken over and your sister is in her own world now.
I'm in several Zoom dementia support groups, and placement is not always easy per other members with their Loved ones. It seems that your sister has settled into her new home very well.
I'd be careful about bringing in items from her home that might upset the balance her brain has established with dementia. Or wait until there may be some stress in her stay there and introduce the items as comforting reminders to her-that you brought up from the basement or attic or garage or back room.... ; )

Look what I found?
Would you like it?

I would say nothing. My brother and I this week took my step-mother, with dementia and in MC, out to lunch for her 85th Birthday.

Overall, she did ok, however while sitting there and looking out the window, she saw several people coming in that that she recognized as being there before.

I said "You remembered them"? Her response was "Yes, I have a good memory"! Now, not reacting to that statement required a great deal of self-control!

She also thought the waitress was her sister because her name was Joyce. She had never been to the restaurant before.

My point is let her believe, it most likely is a comfort for her. There is no harm in letting her think this. As for the things, just say, we brought them here from your house to enjoy.

Less is more when dealing with a dementia patient. Don't try and overexplain anything,

Sending support your way!

I would not tell her. In her mind she is home. That’s a real blessing and as good as it gets for someone in memory care. Confusing her with another home that she sort of remembers living in at some point and telling her you are selling that home will not serve any purpose other than relieving you of whatever guilt you feel for keeping it from her. It will not help her at all. You are doing her a favor by not telling her. You can always pick out a few things that you think she would enjoy having and say “look what we found when cleaning, we thought you might like to have these.” But honestly, if she is content where she is I wouldn’t even give her the items. It may only be distressing and confusing to her.

On another extreme my mom who settled in nicely wherever she was, was always happy but constantly asking the same questions. My dying brother and I decided that we would never tell her when he passed. I would give one of the 2 repetitive responses if she asked where my brother was. That way everybody stayed happy.

Why tell her? If the brain is broken, telling her would just cause sadness for a certain amount of time...and what's the point? Yes, by all means, take her some things that might mean something, but don't be surprised if she doesn't remember them. If she asks, tell her she loaned the item(s) to you one time and thought they would look nice where she is now.

Actually, she's in a good place memory wise. She thinks she's in the old family home where there are some good memories. Leave it at that. Her actual house is just a by-gone memory and the current 'old home' thought is okay with her.

Sell the house so she can stay where she is as long as she can without disrupting her memory status. Having to move can cause a downward spiral with dementia.

Grandma1954 July 30, 2023 4:10 pm
Why tell her you are selling the house.

If she is convinced that the house she is now living in is her family house and you tell her you are selling the family house she may think she is going to have to move.
Let her live in her reality it is doing no harm.

As far as "cherished" items has she asked for anything?
If not then do not bring her anything.
if you do want her to have something and she has not asked for it and she wants to know where it came from tell her you got it at an antique shop in town, or say "this old thing, I've had it for years"
If she says she had one like it say "oh, wow tell me more about it"