I read it too - I also thought she did a brilliant job. Obviously, none of us can know what is really going on inside the mind of someone with mid-stage dementia. But I think Emma Healey did a fantastic job of giving insight to Maud's behaviours - the notes she was writing to remind herself, the "wandering" which wasn't just wandering, but had a purpose - she was going to look for Elizabeth, etc.
Graham Stokes, in his excellent book "And the Music Still Plays" says something along the lines of there being a reason behind every behaviour - but we may never know the reason. I think in Emma Healey's novel, being able to, so to speak, "look out" through Maud's eyes and see the world from her perspective, could only be helpful, in that it reminds us that, as we are going through the day with someone with dementia, we may not be seeing and understanding things the same way.