Grandmother going through it right now. It's very depressing to see an independent woman go through that madness while still believing in her heart of hearts that she's fine despite everything else pointing so far away from that.
For a long time we've been sorta just ignoring it even though we'd all like to say we were just letting her be, but the wondering about, not bathing, leaving the stove/Burners on and putting goddamned rooted up plants, video cassettes and pillow cases in the fridge made that shyt hard to ignore anymore.
And to be honest op I don't think those that know they got it know. In the earliest my Grandmom used to ask the same question over and over, losing damn near all her short term memory. People get mad 'cause they think she's just being annoying....but it's one of the stages, man. Back then she knew her memory was a little bad but she'd still show slight sparks of rational thought until it all went away. S'fukked up. God bless my mom's for stepping up to the plate and getting a sitter who knows her from way back to help us.