How do I tell my mom who’s in stage 6 of AD that her sister has just passed away?

Your Mom probably has forgotten her sister. No need to tell her. Just send flowers saying wish you could be there.

Marty
My uncle just died and I have no intention of telling my 95 y.o. mother with end stage 6 Alzheimer's. Why? So she can obsess with something she can't even comprehend?

Forgetaboutit.

Marty30 I agree with Pepsee. She may get obsessed after you tell her. If she may ask you just tell her she's in a good place I'm sure she misses you too. Something like that.

Hi Marty.
Why would you even tell her? What good will come of it? Does she really NEED to know?