In the middle of this mum refused to go to the doctors. I eventually got her there by stealth and the GP said he would refer her to Social Services. Social Services phoned mum up and asked her what help she needed. Mum said that she didnt need any help at all as she was doing all her own housework, shopping, cooking etc etc. One look at her and her home would have told you that this was not true - her house was in a terrible mess, she was not cooking, or even eating much, she was not washing or changing her clothes, but Social Services took her at her word and crossed her off their books!!!!! By this stage I was pulling my hair out with worry. It took a TIA and a spell in hospital for her to get the help she needed. She went from the hospital to a care home and lived there for the remainder of her life.
The point of all of this is to explain how hard it can be to get help for a person with dementia. Social Services have this policy of keeping them at their own home for as long as possible (IMO, far too long) and if the person with dementia refuses help they will not insist. All you can do is contact the police if you see her outside lost - and especially if it is during the night - and also if you or she is in danger. You could also contact SS to tell them about the affect that it is having on your children. Eventually there will be a crisis and I expect it is likely to be quite soon.