MIL was diagnosed with Alzheimer's when I was pregnant with our first child, DD who is now 4. We also have a 1 year old DS.
The disease is now advanced enough that I think DD might start noticing that her grandmother is a bit 'strange'. She has retained most of her kind personality so far, although she seems to find it stressful having children around and has started to snap at them more and more often. They upset her with their noisiness and unpredictability, especially the little one. She was always a great lover of children but not any more. She is also confused a lot and doesn't always make sense when she's talking, which DD is old enough to notice now. Physically she is still sort of OK, still continent but needs help with various things, but all this is easy to shield the children from. She still lives at home with FIL. We live quite close and see each other fairly frequently (few times per month).
We don't really know how to handle it. Would it be better to keep the children away from her as far as possible? This might upset DD but I suppose being snapped at might upset her more in the long term - I don't think it would upset MIL.
We haven't told them anything so far. Obviously DS could not understand it if we did, but perhaps it is time to tell DD that Granny is not well? I'm just not sure what to say. DD knows about illness and she knows about death, but something in my gut tells me that she might not be ready to know that her grandmother has an illness that is not going to get better. Perhaps it would be best not to tell her anything until we really have to, like when MIL can no longer live at home? DD hasn't asked any questions about it yet, but I can see that she finds some things odd.
I'm all for being truthful with children but when the truth is so cruel and bleak, is it really fair to saddle them with that so young? If your children had a grandparent with Alzheimer's or dementia, what did you tell them and when?